Poly(N,N′‐bis‐4‐butylphenyl‐N,N′‐bisphenyl)benzidine‐Based Interfacial Passivation Strategy Promoting Efficiency and Operational Stability of Perovskite Solar Cells in Regular Architecture

Abstract

The failure of perovskite solar cells (PSCs) to maintain their maximum efficiency over a prolonged time is due to the deterioration of the light harvesting material under environmental factors such as humidity, heat, and light. Systematically elucidating and eliminating such degradation pathways are critical to imminent commercial use of this technology. Here, a straightforward approach is introduced to reduce the level of defect‐states present at the perovskite and hole transporting layer interface by treating the various perovskite surfaces with poly(N,N′‐bis‐4‐butylphenyl‐N,N′‐bisphenyl)benzidine (polyTPD) molecules. This strategy significantly suppresses the defect‐mediated non‐radiative recombination in the ensuing devices and prevents the penetration of degrading agents into the inner layers by passivating the perovskite surface and grain boundaries. Suppressed non‐radiative recombination and improved interfacial hole extraction result in PSCs with stabilized efficiency exceeding 21% with negligible hysteresis (≈19.1% for control device). Moreover, ultra‐hydrophobic polyTPD passivant considerably alleviates moisture penetration, showing ≈91% retention of initial efficiencies after 300 h storage at high relative humidity of 80%. Similarly, passivated device retains 94% of its initial efficiency after 800 h under operational conditions (maximum power point tracking under continuous illumination at 60 °C). In addition to interfacial passivation function, hole‐selective role of dopant‐free polyTPD is also evaluated and discussed in this study.

Metal‐Halide Perovskite Crystallization Kinetics: A Review of Experimental and Theoretical Studies

“…Reproduced with permission. [278] Copyright 2020, Wiley-VCH. www.advancedsciencenews.com various perovskite systems must therefore be performed, as a universal crystallization modulating strategy is highly desirable.…”

“…For example, Akman et al recently reported that poly(N,N′-bis-4butylphenyl-N,N′-bisphenyl)benzidine (poly-TPD) has a strong passivation effect on perovskites. [278] They found that top-coated poly-TPD reacted with Pb defects and thus improved the surface morphology of perovskite films (Figure 24e,f), and that the hydrophobicity of poly-TPD led to substantially enhanced device stability under an ambient atmosphere.…”

“…e,f) Scanning electron microscopy images of perovskite film before and after poly(N,N′-bis-4-butylphenyl-N,N′-bisphenyl)benzidine treatment. Reproduced with permission [278]. Copyright 2020, Wiley-VCH.…”

Tailoring the Interface in FAPbI3 Planar Perovskite Solar Cells by Imidazole‐Graphene‐Quantum‐Dots

“…[ 9–12 ] Moreover, numerous effective strategies have been reported to passivate the surface defects of top region of perovskite interconnecting with the carrier transport layer (CTL), and thus to enhance the stability and performance of PSCs. [ 6,13,14 ] Meanwhile, the bottom interface also plays a critical role in the degradation of perovskite active layer and PSC performance and stability. [ 15–17 ]…”

Solvent‐Additive Engineering‐Assisted Improvement of Interface Contact for Producing Highly Efficient Inverted Perovskite Solar Cells

“…Another polymeric HTL material, namely, poly‐TPD, displays similar energy levels, intrinsic hole mobility, and thermal stability versus PTAA. [ 26–28 ] Nonetheless, an obvious gap in the device performance still exists between poly‐TPD and PTAA‐based IPSCs (21.3% vs 22.7%). [ 29 ] This is because the intrinsic nonwetting property of poly‐TPD makes the perovskite precursor solution difficult to spread out and coat the poly‐TPD surface, giving rise to more serious interfacial contact and recombination losses.…”