Fullerene Polymer Complex Inducing Dipole Electric Field for Stable Perovskite Solar Cells

Abstract

Lead halide perovskite solar cells (PSCs) have demonstrated great potential for realizing low-cost and easily fabricated photovoltaics. At this juncture, power conversion efficiency and longterm stability are two important factors limiting their transition. PSCs exhibit rapid environmental degradation since the perovskite layer is very sensitive to factors such as humidity, temperature, and ultraviolet light. Here, we demonstrate a novel successful approach that simultaneously improves the efficiency and stability of PSCs. This approach relies on incorporation of a dual-functional PMMAfullerene complex into the perovskite layer. The fullerene within perovskite layer forms a localized dipole-like electric field that favors the electron-hole separation resulting in significant improvement in current density and fill factor with conversion efficiency reaching 18.4%. The molecular-scale coating of hydrophobic PMMA on the perovskite grain boundary effectively blocks moisture penetration into the perovskite, thereby, significantly improving the stability against moisture, heat, and light. The PSCs with PMMA-fullerene complex showed no photovoltaic performance degradation for 250 days and exhibited 60 times higher stability compared to the state-of-the-art devices under continuous 1 sun illumination in ambient air.

The role of carbon-based materials in enhancing the stability of perovskite solar cells

“…Incorporation of PMMA-fullerene complex inside the LHP layer resulted in improved performance and stability of PSCs. 179 The fullerene located at the LHP grain boundaries and formed a dipole-like electric field inside the LHP layer. It favored charge carrier separation improving the device performance.…”

Polymer Additives for Morphology Control in High‐Performance Lead‐Reduced Perovskite Solar Cells

“…Nevertheless, excessive replacement of Pb 2+ by Ba 2+ may result in unstable perovskite structure and lead to inferior photovoltaic properties and poor morphology. To solve this problem, polymer additives, including poly(vinylidene fluoride‐co‐trifluoroethylene) [P(VDF‐TrFE)], polymethyl methacrylate (PMMA), and PEG, were added into the lead‐reduced mixed‐cation perovskite to modify the perovskite films.…”

Diagnosis of Perovskite Solar Cells Through Absolute Electroluminescence-Efficiency Measurements

“…High-quality perovskite films with low-density defects are necessary. To obtain high-quality perovskite films with low-density defects, many methods have been proposed: (1) the dual-functional polymethyl methacrylate fullerene complex is incorporated into the perovskite layer to accomplish the improvement in intrinsic stability and charge transport properties of the film [33]; (2) antisolvent assisted crystallization method to obtained superior film [34,35]; (3) incorporation of chlorine in perovskite film enlarges grains increases crystallinity and carrier mobility, reduces electronic disorder and suppresses trap-assisted recombination [36], leading to improved efficiency of devices. Furthermore, interfacial recombination at the perovskite/transport-layer interface dominates the junction energy loss and results in a significant reduction of the potential V oc of the solar cell.…”