Highly stable and efficient solid-state solar cells based on methylammonium lead bromide (CH3NH3PbBr3) perovskite quantum dots

Easy processability and high stability are key features of methylammonium lead bromide (CH3NH3PbBr3)-based perovskite solar cells. The main focus of the present work was to fabricate and evaluate the stability of CH3NH3PbBr3 quantum dot (QD)-based perovskite solar cells. We used an ex situ solution process to synthesize CH3NH3PbBr3 QDs and then successfully fabricated mesoscopic solid-state perovskite solar cells. We also studied the influence of different CH3NH3PbBr3 QD sizes and different hole-transporting materials (HTMs), 2,2′,7,7′-tetrakis-(N,N-di-4-methoxyphenylamino)-9,9′-spirobifluorene (spiro-MeOTAD) and poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA), on the solar cell performance. The size of the CH3NH3PbBr3 QDs was controlled by the solution processing parameters. Our controlled results show that spiro-MeOTAD- and PTAA-based devices exhibited, respectively, an open-circuit voltage (VOC) of 0.991 and 1.091 V and a current density (JSC) of 11.68 and 12.05 mA cm−2, which resulted in an average power conversion efficiency (PCE) of 7.35 and 9.44% under a standard 100 mW cm−2 illumination without masking. Our best-performing cell, which contains the FTO/Bl-TiO2/mp-TiO2+CH3NH3PbBr3 (~2-nm QDs)/PTAA/Au configuration shows the following results: open-circuit voltage (VOC)=1.110 V, current density (JSC)=14.07 mA cm−2, fill factor=0.73 and an 11.40% PCE. Furthermore, the CH3NH3PbBr3-based devices are stable for more than four months. Highly stable and efficient solid-state solar cells have been made based on perovskite quantum dots of methylammonium lead bromide (MAPbBr3). Sawanta Mali, Chang Su Shim and Chang Kook Hong of Chonnam National University in South Korea fabricated highly crystalline MAPbBr3 quantum dots by an ex situ process using dimethyl sulphoxide as a solvent and then examined their performance in perovskite solar cells having two different hole-transporting materials. They also produced quantum dots of different sizes by varying the solution processing conditions and found that the solar-cell performance depended significantly on the quantum dot size. The team obtained a maximum conversion efficiency of 11.46% when poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] was used as the hole-transporting material and MAPbBr3 quantum dots with diameters smaller than three nanometres were used. They found that the solar cells were stable over a four-month period. Development of methylammonium lead halide perovskites for efficient solar cell is best approach towards efficient building photovoltaic. This article demonstrates the synthetic strategy for the synthesis of efficient and stable CH3NH3PbBr3 quantum dots for efficient mesoscopic solid-state perovskite solar cells. The influence of different CH3NH3PbBr3 quantum dot size and different hole-transporting materials has been discussed systematically.