Advanced imaging for perovskite solar cells
Combining the expertise between two photovoltaic characterisation teams at the Australian National University (ANU) and Fraunhofer-ISE, we aim to develop a series of imaging methods to spatially resolve critical optical and electrical parameters of perovskite solar cells and materials. Particularly, the project will focus on light-based imaging techniques for implied open circuit voltage iVoc and its temperature coefficient, ideality factor nid, activation energy Ea of recombination, sub-bandgap absorptivity, minority carrier lifetimes, and posiibly series and shunt resistances for various perovskite structures. It may also adopt some of these mentioned techniques to characterise subcells in silicon-perovskite tandem solar cells.
Status: Ongoing
Date of proposal: 28/07/2022
Start date: 04/10/2022
End Date: 09/12/2022
Used Instruments: PL imaging system with two lasers (450 nm and 808 nm). Calibrated halogen lamp for absolute calibration of PL intensity.
Experimental Technique: Absolute calibration of PL intensity and its application to the Suns-PL method. Quantification of the Luminescence. Coupling (LC) effect in perovskite/Si tandem solar cells.
Experiment Description: The project aimed to absolutely calibrate PL intensity for spatially resolved performance analysis of perovskite/Si tandem solar cells and quantify the PL coupling effect in these cells. The study included capturing PL images using specific lasers and filters, and validating the method on III-V semiconductor devices and standard Si solar cells.
Type Samples: Monolithic perovskite/Si tandem solar cell. III-V semiconductor device and standard Si solar reference cell (for method validation).
Sample Description: PL images captured for each subcell of the tandem device using different lasers and band-pass filters.
Experiment Data Type: Injection-dependent iVoc images. Photoluminescence quantum yield (PLQY) measurements.
Characterization Technics: PL imaging for capturing photoluminescence of subcells. Validation using calibrated lifetime images and absolute PL spectra.
Characterization Data Type: Spatially resolved measurements of iVoc for each subcell. Comparison of PL intensity with lifetime and terminal Voc measurements.
Analyzed Data: Validation of the absolute PL Imaging method. Analysis of the luminescence coupling efficiency in a 2T perovskite/Si tandem solar cell.
Main Targets Project: Absolute calibration of PL intensity for analyzing perovskite/Si tandem solar cells. Quantification of luminescence coupling effect in tandem cells.
Main Achievements Findings: Developed a method to measure iVoc maps using absolute PL Imaging, validated using calibrated lifetime images and PLQY setup. Proposed a method to experimentally obtain the LC efficiency of a 2T perovskite/Si tandem solar cell, complemented by an optic simulation model. Demonstrated the capability of the method to provide spatially resolved measurements and locate defective regions in the cells.
Review 14
How would you describe your experience with the VIPERLAB opportunity? How did the experience/visit at Fraunhofer Institute for Solar Energy Systems (Fraunhofer-ISE) meet your expectations?
The VIPERLAB opportunity has been an exceptional experience. Through the support of the VIPERLAB project, we were granted the opportunity to visit one of the world's leading solar cell research centers, Fraunhofer-ISE. At Fraunhofer-ISE, we had the privilege of engaging with experts in the field and gaining access to state-of-the-art laboratory equipment. Daily discussions with colleagues at Fraunhofer-ISE expanded our horizons and provided valuable insights for our research topics.
Did you face any difficulties during your visit or application process?
Fortunately, we encountered no difficulties during our visit or the application process. Colleagues at Fraunhofer-ISE, particularly Martin Schubert, Florian Schindler, and Oliver Fischer, provided tremendous support throughout the entire journey, assisting us with the application process, visa applications, and granting access to the laboratory facilities.
Does this VIPERLAB experience at Fraunhofer-ISE bring you closer to your research objectives? How?
Absolutely! Our experience at Fraunhofer-ISE through VIPERLAB has significantly brought us closer to our research objectives. Engaging in fruitful discussions with colleagues at Fraunhofer-ISE, we delved into various intriguing research topics, such as voltage-dependent series resistance, absolute calibration of photoluminescence images, and photoluminescence coupling effects in tandem solar cells. These ideas and discussions are invaluable in advancing our research objectives.
What other VIPERLAB activities have you participated in, or would you like to participate in?
In addition to attending the "2nd VIPERLAB Workshop on Precise measurements of Perovskite Silicon Tandem Solar cells," we are eager to participate in future VIPERLAB activities, particularly online workshops. We have found immense value in these events and believe they provide excellent learning opportunities for further expanding our knowledge and expertise.
Do you intend or already did publish/present your collected results in a paper or conference?
Yes, we have already submitted one paper that acknowledges the support we received from VIPERLAB. Furthermore, we plan to submit at least two additional manuscripts in the near future, where we will continue to acknowledge the invaluable assistance provided by VIPERLAB.