As the power required for the electronic device (e.g., sensors, actuators) continues to decrease, the use of indoor photovoltaic cells to power billions of wireless devices to collect the big data for a future IoT nodes is becoming possible, of which the self-powered characteristic can reduce the use of batteries and avoid battery replacement. Different from solar illumination, the modern indoor light (fluorescent, LED) has its specific spectra (300-650 nm), which therefore requires for a special design of the photovoltaic cells. Mr. Rui Cheng, Dr. Chih-Chun Chung and Dr. Shien-Ping Feng developed a triple-anion CH3NH3PbI2-xBrClx perovskite film, of which the bandgap is specially designed to better fit the indoor light spectra to achieve a record high efficiency of 36.2%, over performing all the state-of-art indoor photovoltaic cells. The involvement of both bromide and chloride suppresses the trap-states and non-radiative recombination loss, exhibiting a remarkable ideality factor of 1.097. The introduction of chloride successfully restrains the halide segregation of iodide and bromide, stabilizing the triple-anion perovskite film. The devices show an excellent long-term performance of sustaining over 95% original efficiency under continuous light soaking over 2000 hours. The findings show the importance and potential of I/Br/Cl triple-anion perovskite with tailored bandgap and suppressed trap-states in stable and efficient indoor light recycling.
This research is published in Advanced Energy Materials, and the full article is available in the following website: https://onlinelibrary.wiley.com/doi/full/10.1002/aenm.201901980
This work has been selected for the front cover of the volume 9, issue 38. https://onlinelibrary.wiley.com/doi/abs/10.1002/aenm.201970146