Progress 05/01/21 to 04/30/22
Outputs
Target Audience:During this reporting period, NanoFlex installed Ensora sensors at three indoor farms, increasing visibility of the Ensora Systems among indoor farmers and greenhouse installers. NanoFlex also has a website launched at ensorasystems.com and generated online traffic and marketing using our partner markering agency BlueStar. We are buildling brand awareness among indoor farmers to drive sales volume upon a future produce launch of our energy harvesting wireless sensor system. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?
Nothing Reported
How have the results been disseminated to communities of interest?
Nothing Reported
What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
Objective 1: OPVmoduleintegration into Ensora sensors 1) Activities/experiments conducted NanoFlex designed and optimized our Organics Photovoltaics (OPV) for maximum energy harvesting in indoor light found in indoor farms and greenhouses. 2) Data Collected The OPV device performance was measured at 250 - 50,000 lux levels of white LED light (indoor farm) and 1 sun (greenhouse). Our performance targets for OPVs were focused on lower light levels (250-500 lux) to ensure the robust and reliable operation of Ensora sensors using energy produced by the OPV even in low light conditions. 3) Summary statistics and results Our OPV development led to a 3-fold performance improvement with the final champion performance exceeding the target power conversion efficiency requirement at 500 lux by 33%. Such improvement was achieved via careful data-driven analysis and optimization of power generating layers (also known as active layers that absorb light and convert it into current) within the OPV device stack. 4) Key outcomes/accomplishments We fabricated 30 OPVs capable of self-powering sensors in indoor farm lighting. The OPVs are integrated into Ensora sensors in Objective 2. Objective 2: OPVmoduleintegration into Ensora sensors 1) Activities /experiments conducted Under lab conditions, we demonstrated OPV-powered sensors that can measure temperature, humidity, light, and CO2, and then transmit that data wirelessly, including: We revised the plastic cases of the sensor to accommodate the OPV module and to provide a hermetic seal with it to prevent water from entering We constructed and programmed 30 fully operational OPV-powered Ensora sensors and 5 gateways We demonstrated the charging of the battery using the integrated OPV modules We demonstrated receiving wireless data from the Ensora sensor We calibrated our lux sensor while installed in the module using a calibrated light source for light intensities between 0 and 1 sun 2) Data collected We collected data on the power available for the Ensora sensor from the integrated OPV module and charge controller We collected data on the response of our PAR/lux sensor to different light levels We collected data on the effectiveness of the Ensora sensor to accurately measure temperature in direct sunlight 3) Summary statistics and results For greenhouse-like conditions, the power harvested by the OPV module is more than enough to operate the attached sensors and radio, and the internal battery of the sensor can be fully charged rapidly, over only one or two days. 4) Key outcomes/accomplishments We demonstrated that our OPV modules are capable and effective for powering our IoT wireless sensor system for indoor-agriculture applications. This has the potential to be adopted by indoor farmers, and it validates the technology for use in other markets. Objective3: Field testing 1) Activities/experiments conducted Our field-testing team deployed approximately 5 sensors to each of 3 different indoor farm locations. 2) Data collected Sensor battery level was monitored over time and sensor values were compared to third-party sensor sensors. 3) Summary statistics and results Ensora sensors were installed, transmitting environmental conditions for 4 months at the time of this report. The OPV sheets provide enough energy to power the Ensora sensors in the light found in indoor farms. Ensora sensors were found to be accurate compared to third-party sensors. 4) Key outcomes/accomplishments Field testing validation of Ensora sensors demonstrated that sensors can be powered in indoor lighting and that wireless transmission of data is reliable, increasing consumer confidence in the Ensora sensor system. Objective4: Demonstration of automation capabilities 1) Activities/experiments conducted We demonstrated the basic viability of our sensors for informing automation systems by turning a fan on and off based on transmitted temperature readings, including: Produced a functioning Automation Hub electronics assembly Programmed the Automation Hub with firmware that permits user-defined automation routines Demonstrated the operation of such a routine with a fan connected to the Automation Hub, using an Ensora sensor as the controlling sensor 2) Data collected We demonstrated an Automation Hub controlling a fan based on temperature readings from a wireless Ensora sensor. 3) Summary statistics and results The demonstration is an example piece of environmental conditioning equipment operating in a thermostat mode using the wireless Ensora sensor as the temperature sensor. The system works as intended, providing initial validation for the use of the Ensora system in environment control applications such as indoor agriculture. 4) Key outcomes/accomplishments We demonstrated that our OPV-enabled Ensora system can be used not only to help farmers monitor their indoor environment, but also to control it.
Publications
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Progress 05/01/21 to 12/31/21
Outputs
Target Audience:NanoFlex has presented the Ensora Systems at two conferences, increasing awareness of the upcoming product to the indoor agriculture community. Dr. Richard Field III gave a talk at the 2021 HoritCann Light+Tech conference, discussing using LED Light Harvesting to power a complete wireless sensor network and environmental control system. Then, NanoFlex had an exhibitor booth at the 2021 Indoor AgCon conference for Ensora Systems, providing awareness of the Ensora wireless sensors plus automation system. At these conferences we received confirmation from growers, indoor farm installers, control system providers, educators, and students about the importance of reliable wireless sensors. NanoFlex received interest from many growers and indoor farm installers to participate in upcoming field testing of Ensora Systems. Of note, a high school teacher signed up for a future Ensora trial in her classroom so that her students can learn about indoor growing and controlled environmental agriculture firsthand, and Northern Michigan University wants to partner with Ensora for their new indoor agriculture program. Changes/Problems:NanoFlex development is continuing as planned with development of OPV modules for integration into Ensora sensors in progress. The development timeline has been delayed due to the global chip shortage. Notably, there was a 3-month delay getting PCBAs for the Ensora Automation Hub and Gateway due to long lead times for critical chips and components. This is creating a 3-month delay of Task 2 OPV Module Integration into Ensora Sensors (originally completed October 2021 now completed January 2022), Task 3 Field Testing (originally completed December 2021 now completed March 2022), and Task 4 Demonstration of Automation Capabilities (originally completed October 2021 now completed March 2022). To account for this delay and a potential future delay due to the global chip shortage, NanoFlex is submitting a no-cost extension request to extend the program by 4 months to April 30, 2022. This extension does not change any of the research goals or expected outcomes of the program. What opportunities for training and professional development has the project provided?
Nothing Reported
How have the results been disseminated to communities of interest?NanoFlex has presented the Ensora Systems at two conferences, increasing awareness of the upcoming product to the indoor agriculture community. Dr. Richard Field III gave a talk at the 2021 HoritCann Light+Tech conference, discussing using LED Light Harvesting to power a complete wireless sensor network and environmental control system. Then, NanoFlex had an exhibitor booth at the 2021 Indoor AgCon conference for Ensora Systems, providing awareness of the Ensora wireless sensors plus automation system. At these conferences we received confirmation from growers, indoor farm installers, control system providers, educators, and students about the importance of reliable wireless sensors. NanoFlex received interest from many growers and indoor farm installers to participate in upcoming field testing of Ensora Systems. Of note, a high school teacher signed up for a future Ensora trial in her classroom so that her students can learn about indoor growing and controlled environmental agriculture firsthand, and Northern Michigan University wants to partner with Ensora for their new indoor agriculture program. What do you plan to do during the next reporting period to accomplish the goals?Outside of our no-cost extension due to global supply shortages (NanoFlex is submitting a no-cost extension request to extend the program by 4 months to April 30, 2022), our team is on track with the major objectives detailed in our Phase I proposal. During the next reporting period, we will: · Transfer optimized OPV devices structures to the new OPV sheet design established in the first reporting period. · Integrate optimized OPV sheets into a proof-of-concept Ensora sensor stack that can measure temperature,humidity, light, and CO2, transmitting that data via a Bluetooth low energy radio. · Produce and install 30 OPV-powered, wireless IoT sensors in 1 vertical farm and 4 greenhouses for 2-3 months of real-world field testing. · Demonstrate the basic viability of our sensors for informing automation systems by turning a fan on and off based on transmittedtemperature readings. The automation will be driven by our Ensora grow-controlled cloud software.
Impacts
What was accomplished under these goals?
What is the problem that your project addresses? NanoFlex is developing a complete self-powered wireless sensor network and automation system using breakthrough Organic Photovoltaic (OPV) technology, which has superior energy harvesting in indoor light enabling self-powered sensors in any lighted condition. Who will be most immediately helped by your work, and how? This system is simple and low-cost to install with place-and-forget sensors, facilitating adoption of critical environmental controls by farmers. The complete system is cloud connected for offsite control and monitoring of grow conditions and automation status, and also runs locally so that the system is reliable and does not depend on a constant internet connection to operate. What was accomplished for each goal? Progress during this reporting period focused on Task 1, OPV module development. The remaining Tasks will be accomplished during the next reporting period. Task 1: OPV module development Summary: NanoFlex will modify the design of our current OPV modules to integrate seamlessly into our first generation Ensora wireless sensors and maximize power conversion efficiency (PCE) under low-light conditions to provide the largest possible power budget for the sensor systems. Deliverables: OPV modules with the necessary footprint and electrical connections for integration into Ensora sensor system packaging Demonstrate tuned spectral response and improved efficiency of the OPV modules under customer-indicated grow lights Demonstrate increased shunt resistance due to thicker active layers, modified cleaning procedures, substrate surface treatments, and/or introduction of passivation layers 1.1 Indoor light testing station and baseline OPV performance NanoFlex designed and built an indoor light station to test the performance of OPV sheets at conditions mimicking indoor agriculture illumination settings. Discussions with our indoor farm partners Ceres and Brighterside indicate that they employ white LED light for indoor or supplemental outdoor lighting. We designed our indoor light station to operate in the 250-50k lux range, covering the range including dim/shadowed light and bright lights. We are using dimmable PAR700 700W LED grow light from ViparSpectra as a representative white LED grow lamp. The LED light intensity uniformity was optimized to achieve 100% uniformity over the entire OPV sheet in the target lux range. The LED light station consists of a light-tight enclosure, an LED light source with tunable light levels of up to 50k lux, and a current-voltage (IV) testing setup. To establish the internal baseline low-light performance of NanoFlex OPV sheets and to test the low-light enclosure, we first measured our existing outdoor OPVs (optimized for 1-sun illumination) in the indoor light station. NanoFlex's outdoor OPV sheets consist of 6 cells connected in series on a 6x7 cm2 glass substrate. The OPV sheets are encapsulated on the topside using a glass cover held with epoxy and edge sealant, with electrical connectors protruding through one of the edges. The OPV active layers absorb and convert light to electricity and are sandwiched between two electrodes - the anode such as Indium Tin Oxide (ITO) which is transparent to let light through to the active layer (the "front" or "illumination side"), and the metal cathode such as Al (the "back side"). The OPV active layer has thickness of 120 nm and consists of a blended electron donor (D) and electron acceptor (A) film with a blend ratio of D:A = 1:2. The outdoor OPV sheet was tested at 250, 500, 5k, and 50k lux levels. The PCE for these OPV sheets varies from ~13% at 50K lux to ~7% at 250 lux. 1.2 Power budget for minimal light conditions and OPV performance development The minimum power requirements of OPV sheets were calculated to provide enough power for Ensora sensors to run continually in low light (500 lux) conditions, measuring and wirelessly transmitting sensor values such as temperature, relative humidity, CO2, and light intensity (lux/par). For continuous readings of these sensors in low light with light on 16 hours/day, the following requirements of OPV sheet power generation have been determined: Estimated average power - 265 µW OPV needs to generate Pmax 596 µW Estimated PCE - 15% This estimate includes a safety factor of 1.5X, enabling measurements in lower light and/or illumination for a few hours each day. Also, this is the power requirements for continuous sensor measurement every few seconds; if less energy is harvested below the safety factor the sensors will continue to work, transmitting data less frequently using a power management algorithm. At 500 lux, NanoFlex's baseline OPV (optimized for outdoor applications) generates 533 µW with PCE = 8%. This OPV has shunt resistance (Rshunt) of ~5 MOhmscm2 with a fill factor (FF) of ~62%. To achieve the target PCE and Pmax in low light, the FF needs to be improved via optimization of Rshunt to nearly double it. We have determined that the main cause for low Rshunt is the interaction between the packaging epoxy and OPV layers, which cracks the OPV layers during the encapsulation process. Our OPV cells use a UV-curable epoxy, Delo LP655, to attach the cover glass to the OPV so that all OPV layers are sandwiched between 2 glass sheets. The temperature of the OPV sheet reaches ~65-70 C during UV curing. To chemically protect OPV layers from reactions with liquid Delo before curing, we cover OPV with a protective layer of MoO3 prior to encapsulation using Delo. We have discovered that this MoO3 film is thermally mismatched with Delo; namely, the coefficient of thermal expansion (CTE) of MoO3 is ~5 ppm/K1 while the CTE of Delo is ~80 ppm/K.2 This thermal mismatch leads to MoO3 films cracking during UV curing of Delo, lowering Rshunt which in turn lowers FF and PCE. To solve this issue, we have optimized the protective layer by adding a film of LiF between MoO3 and Delo, making a new protective layer to be MoO3/LiF. This new device structure has no cracks and leads to significantly improved OPV performance. Shunt resistance was more than doubled with Rshunt = 12 MOhmscm2, leading to PCE = 17% and Pmax = 620 µW at 500 lux. Further improvement in performance was achieved by increasing thickness of active D:A layer from 120 nm to 160 nm leading to ~2x increase in generated photocurrent and therefore PCE. The new champion PCE is 20% at 500 lux. Thus, the NanoFlex OPV team has successfully improved the OPV materials and device structures and achieved our performance targets to provide enough power for continuous operation of Ensora sensors even at the lowest light conditions. Currently we are working on fabrication and optimization of the OPV devices with the new layout specifically designed to fit Ensora. 1.3 OPV design and electrical connections development for Ensora sensors system To integrate OPV sheets into the Ensora power module, the OPV sheets have been redesigned with the following specifications: target size for Ensora OPV sheet including packaging - 6x5.5 cm2 Ensora OPV device layout - 4 cells connected in series to achieve battery-charging voltage of 1-4 V Pmax > 596 µW at 500 lux We have ordered glass/ITO substrates and cover glass sheets for the new Ensora layout. Fabrication tooling for the new Ensora OPV layout has also been ordered, including the substrates holder and masking. The OPV fabrication for Ensora sensors is scheduled to start in mid-November. What did your project do about this problem? As described above, NanoFlex improved the energy harvesting of OPVs under indoor lighting. This will enable self-powered wireless sensors which will be field tested in greenhouses and a vertical farm. References 1 https://www.msesupplies.com/pages/list-of-thermal-expansion-coefficients-cte-for-natural-and-engineered-materials) 2 https://www.delo-adhesives.com/fileadmin/datasheet/DELO%20KATIOBOND_LP655_ %28TIDB-en%29.pdf)
Publications
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2021
Citation:
Field III, R. L. (2021, September 28-29). Using LED light harvesting to power a complete wireless sensor network and environmental control system [Conference presentation]. HortiCann Light + Tech Conference, online.
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