Regulating Surface Termination for Efficient Inverted Perovskite Solar Cells with Greater Than 23% Efficiency

Abstract

Passivating surface and bulk defects of perovskite films has been proven to be an effective way to minimize nonradiative recombination losses in perovskite solar cells (PVSCs). The lattice interference and perturbation of atomic periodicity at the perovskite surfaces often significantly affect the material properties and device efficiencies. By tailoring the terminal groups on the perovskite surface and modifying the surface chemical environment, the defects can be reduced to enhance the photovoltaic performance and stability of derived PVSCs. Here, we report a rationally designed bifunctional molecule, piperazinium iodide (PI), containing both R 2 NH and R 2 NH 2 + groups on the same six-membered ring, behaving both as an electron donor and an electron acceptor to react with different surface-terminating ends on perovskite films. The resulting perovskite films after defect passivation show released surface residual stress, suppressed nonradiative recombination loss, and more n-type characteristics for sufficient energy transfer. Consequently, charge recombination is significantly suppressed to result in a high open-circuit voltage (V OC ) of 1.17 V and a reduced V OC loss of 0.33 V. A very high power conversion efficiency (PCE) of 23.37% (with 22.75% certified) could be achieved, which is the highest value reported for inverted PVSCs. Our work reveals a very effective way of using rationally designed bifunctional molecules to simultaneously enhance the device performance and stability.

Optimized Carrier Extraction at Interfaces for 23.6% Efficient Tin–Lead Perovskite Solar Cells

“…3d), 0.06 V below the thermodynamic limit of 0.97 V 54 . This corresponds to a voltage loss of 0.33 V − one of the best results thus far for perovskite devices 35,55 . The low voltage loss together with the long charge carrier lifetimes observed in the PL experiments confirm the remarkable suppression of non-radiative recombination channels in the EDAI2/GlyHCl-treated devices.…”

“…Meanwhile, very recently, we achieved ultra-long carrier lifetimes (>7 µs) by applying a Sn(IV) scavenging method 18 and treating the purified Sn-Pb films with maltol 26 . Even with these long lifetimes, however, the efficiencies of mixed Sn-Pb devices 7,[23][24][25][27][28][29][30][31][32][33][34] still remain below those of their pure lead counterparts [35][36][37][38][39] . As the quality of the material already appears to sufficiently high, we believe that the efficiency of Sn-Pb PSCs is now primarily limited by poor carrier dynamics at the interfaces with the charge collection layers.…”

A Cost‐Effective D‐A‐D Type Hole‐Transport Material Enabling 20% Efficiency Inverted Perovskite Solar Cells†

“…[ 8 ] In terms of inverted PVSCs, HTMs play an essential role in charge collection or blocking at the interface and can also affect the crystal growth of perovskite. [ 9 ] Therefore, considerable efforts have been devoted to developing dopant‐free HTMs for improving the efficiency of inverted PVSCs.…”

“…[ 11 ] However, the acidity and hygroscopicity of PEDOT:PSS cause deterioration to device stability. PTAA achieved the highest efficiencies in the state‐of‐the‐art inverted PVSCs, [ 9,12 ] but it is synthesized at a high cost of 1980 USD g –1 and often needs p‐type doping or surface treatments. [ 6,13‐14 ]…”

Organic–inorganic hybrid perovskite for low-cost and high-performance xerographic photoreceptors

“…In the recent decade, the perovskite materials have been intensely investigated for their applications in solar cells, light-emitting diodes, photodetectors, and laser. [13][14][15] These research activities inspired us to explore their application in xerographic photoreceptors.…”