[17p-G202-1~21] 12.5 Organic solar cells

▼ [17p-G202-18] Origin of Open Circuit Voltage in wide band gap absorbers of all inorganic Cesium Perovskite Solar Cells

〇Teresa Ripolles¹, Chi Huey Ng², Kengo Hamada¹, Siow Hwa Teo², Hong Ngee Lim², Juan Bisquert^3,4, Shuzi Hayase¹ (1.Kyushu Institute of Technology, 2.Universiti Putra Malaysia, 3.Institute of Advanced Materials, 4.King Abdulaziz University)

Keywords:Renewable energy, Perovskite, Photovoltaic

Wide band gap absorbers were synthesized based on cesium lead bromide and iodide mixture in perovskite solar cells, CsPbBr_3-xI_x, where x varies between 0, 0.1, 0.2, and 0.3 molar ratio. High photoconvertion efficiencies were performed of 3.98 % for the perovskite composition of small amount of iodide as CsPbBr_2.9I_0.1. We observed that the open circuit voltage V_oc depends mainly of two factors, which are (i) the band gap of the perovskite and (ii) the work function of the hole transport material HTM. An increment in V_oc was observed for the device with larger perovskite band gap, while keeping the electron and hole extraction contacts the same. Additionally, the bilayer P3HT/MoO₃ with deeper HOMO level instead of spiro-OMeTAD as HTM, thus increased the V_oc from 1.16 V to 1.3 V for CsPbBr₃ solar cell, although the photocurrent is lowered due to charge extraction issues. The stability was also investigated which confirmed that the addition of small amount of iodide into the CsPbBr₃ perovskite is necessarily to stabilize the cell performance over time.