Effect of temperature annealing treatments and acceptors in CH₃NH₃PbI₃ perovskite solar cell fabrication

The effects of perovskite solar cells (PSCs) using different temperature annealing treatments and various materials as an acceptor were studied, respectively. The device was composed of an indium tin oxide/poly (3,4-ethylenedioxythiophene):poly (styrenesulfonate)/CH₃NH₃PbI₃ (different temperature annealing treatments)/acceptor materials/bathocuproine/Ag structure. The thermal annealing treatments of CH₃NH₃PbI₃ layers were conduct from 60 to 120 °C. The result showed that the temperature of annealing treatments have significant influences on the power conversion efficiency (PCE) of device. In addition, the acceptor materials used in the device were C₆₀, C₇₀ and 3,4,9,10-perylenetetracarboxylic bisbenzimidazole (PTCBI), respectively. It showed that the mechanism of PSCs is similar to the concept of organic solar cells which is the donor/acceptor interface to dissociate the electron-hole pair via the energy level difference to produce the photovoltaic effect. Furthermore, the short circuit current density and the PCE of device using C₇₀ as acceptor is higher than that of device using C₆₀ or PTCBI as acceptor, which is attributed to the appropriate energy level offset and higher conductivity of C₇₀.