2D Polymers with Lead Anchoring Groups Enable Perovskite Solar Cells with Over 24% Efficiency

Abstract

The hygroscopic dopants used in Spiro‐OMeTAD hole‐transport materials (HTMs) in n–i–p perovskite solar cells (PSCs) inevitably cause device degradation. Herein, two polymer interface materials based on lead anchoring groups are developed. It is found that 2D polymers 2DP‐BT and 2DP‐Por can form dense films and exhibit excellent hydrophobicity. Importantly, 2DP‐Por can passivate the surface defects through noncovalent interactions, reducing nonradiative recombination loss. After introducing these polymer interface materials between the perovskite layer and the HTM layer, the optimized devices using 2DP‐Por and 2DP‐BT achieve champion power conversion efficiency of 24.12% and 23.29%, respectively, and the stability is significantly improved. These results indicate that developing polymer interface materials containing lead anchoring groups can improve PSC efficiency and stability and elucidate critical molecular design rules for interface materials.

Defect Passivation Enabled by Amphiphilic Polymer Additives for Perovskite Solar Cells with Suppressed Charge Recombination

“…It was found that the HI of devices significantly decreased from 0.116 to 0.065 after p­(HEMA- co -DEAMA) modification, indicating reduced channels for ion migration. The integrated J SC values were 23.01 and 23.69 mA/cm 2 for the control and p­(HEMA- co -DEAMA)-modified devices via external quantum efficiency (EQE) spectra (Figure b), which roughly matches the data extracted from the J–V curves . To evaluate the effect of p­(HEMA- co -DEAMA) doping on the overall optical stability of the device, we further tracked the PCE of the corresponding devices in the steady-state at the point of maximum power.…”

“…The integrated J SC values were 23.01 and 23.69 mA/cm 2 for the control and p(HEMA-co-DEAMA)modified devices via external quantum efficiency (EQE) spectra (Figure 5b), which roughly matches the data extracted from the J−V curves. 30 To evaluate the effect of p(HEMA-co-DEAMA) doping on the overall optical stability of the device, we further tracked the PCE of the corresponding devices in the steady-state at the point of maximum power. As displayed in Figure 5c, the steady-state PCE of the unmodified device was only 19.40% with a constant bias of 0.83 V, and there was a significant attenuation after 250 s. For device doped with p(HEMA-co-DEAMA), the stabilized PCE is 20.80% with a constant bias voltage at 0.88 V. Most importantly, the device shows better optical stability with almost no attenuation within 250 s, revealing that the operational photovoltaic device is stable.…”