Conjugated Polyelectrolyte-Passivated Stable Perovskite Solar Cells for Efficiency Beyond 20%

Abstract

Developing large-scale perovskite solar cells requires highquality defect-free perovskite films with improved surface coverage. One of the most convenient ways to achieve this is through the incorporation of appropriate passivation molecules in the perovskite films. Herein, the effect of a novel conjugated polyelectrolyte, PHIA, is investigated for perovskite passivation by the comprehensive analysis of perovskite films and devices. The PHIA polymer significantly diminishes the trap states in perovskite films, and the passivated device permits lesser recombination, very low accumulation of charges at the interface, and lowers the traps which facilitated superior charge transport. As a result, a high power conversion efficiency of 20.17% has been achieved for the PHIA-modified device. Additionally, this passivation approach effectively enhanced the long-term device stability by improving the hydrophobicity of the perovskite layer. Furthermore, a large-area device (2 cm 2 ) has also been fabricated to demonstrate the expediency of this approach for future commercialization.

Multifunctional π‐Conjugated Additives for Halide Perovskite

“…Metallic lead is known to be the main nonradiative center and detrimental to the performance of the PSCs. Lots of reported conjugated molecules for PSCs anchor to the perovskite film via incorporation with uncoordinated Pb 2+ by amino groups, [ 46 , 49 , 53 , 69 ] carbonyl groups, [ 27 , 43 , 51 , 68 ] cyano groups, [ 51 ] sulfur atoms, [ 58 , 67 ] or fluorine atoms. [ 28 , 29 ] In PeLEDs, poly[(9,9‐bis(3’‐( N , N ‐dimethylamino)propyl)‐2,7‐fluorene)‐alt‐2,7‐(9,9‐dioctylfluorene)] (PFN), [ 73 ] PFN‐X (I, Br, Cl), [ 74 ] poly(9,9‐di‐n‐octylfluorenyl‐2,7‐diyl) (PFO), [ 75 ] poly(9,9‐bis(4′‐sulfonatobutyl)fluorene‐alt‐1,4‐phenylene) potassium (FPS‐K) and poly(9,9‐bis(4′‐sulfonatobutyl)fluorene‐alt‐1,4‐phenylene)tetramethylammonium (FPS‐TMA), [ 76 ] poly(fluorene‐ co ‐phenylene)‐based anionic conjugated polyelectrolytes, [ 77 ] and 1,3,5‐ tris (bromomethyl) benzene (TBB) [ 78 ] are reported to dramatically improve the device performance by defect passivation.…”

Enhanced Thermal Stability of Planar Perovskite Solar Cells Through Triphenylphosphine Interface Passivation

“…The TPPpassivated perovskite films exhibit higher PL intensity when compared to the pristine perovskite film, demonstrating less non-radiative recombination in the passivated films. [39][40][41] The time-resolved photoluminescence (TRPL) measurements were conducted to study the effect of TPP passivation on perovskite film. It was observed that TRPL spectra also show a longer lifetime in the TPP-passivated perovskite film (τ = 82.1 ns) than that of the pristine (τ = 59.4) perovskite film, as displayed in Figure S2c.…”

“…The absorption of TPP‐passivated perovskite films shows a slight decrease relative to the pristine film, whereas all films exhibit a similar PL profile (emission peak at ≈763 nm), with only a minimum shift in peak position for the TPP‐passivated films, on excitation with 580 nm. The TPP‐passivated perovskite films exhibit higher PL intensity when compared to the pristine perovskite film, demonstrating less non‐radiative recombination in the passivated films [39–41] . The time‐resolved photoluminescence (TRPL) measurements were conducted to study the effect of TPP passivation on perovskite film.…”

Polymers in High-Efficiency Solar Cells: The Latest Reports

“…The passivated device exhibited minimum charge collection at the interface, lower recombination and lesser traps, allowing for an improved charge transfer. As a result of the passivation, the device had a high PCE of 20.17% (0.50 mg mL −1 of PHIA) [ 156 ].…”