On the role of carboxylated polythiophene in defect passivation of CsPbI ₂ Br surface for efficient and stable all‐inorganic perovskite solar cells

Abstract

Summary Improved film surface is a prerequisite to achieve high photovoltaic performance of inorganic perovskite solar cells because defective (under‐coordinated) lead ions derived from imperfect lattice structure of the film surface or grain boundaries the principal nonradiative recombination centers in the inorganic perovskite absorber. In this study, we suggest poly[3‐(4‐carboxybutyl)thiophene‐2,5‐diyl] (P3CT), a carboxylated p‐type conjugated polymer, as a passivating agent of the CsPbI2Br layer to tailor electronic properties of a perovskite absorber. With the P3CT passivation, the defective sites of the perovskite film surface were improved and stabilized, which can suppress nonradiative recombination to promote charge transport of CsPbI2Br‐based all‐inorganic perovskite solar cells. Consequently, the P3CT passivation delivers a power conversion efficiency (PCE) of 12.25% and decent long‐term stability of CsPbI2Br perovskite solar cells, which surpasses the pristine device without the passivation. The electricity generation capability under indoor light source of the passivated device is also studied, demonstrating a promising PCE of 27.47%. This work unveils the role of P3CT as a passivating agent to passivate the defective sites of CsPbI2Br perovskite film surface and grain boundaries, which facilitates charge transport and reduced carrier recombination of CsPbI2Br absorber in solar cell devices.

Significant Lifetime Enhancement in QLEDs by Reducing Interfacial Charge Accumulation via Fluorine Incorporation in the ZnO Electron Transport Layer

“…In case of the ZnO-EOD, the characteristics show a well-defined inflection point at around 2 V. The FZnO-EOD characteristics, in contrast, show what could be a much less defined inflection point at below 0.5 V, although, given the lower current levels in this case (below 1 µA cm −2 ) instrument limitations can make the measurements accuracy less certain. The clear change in slope at the inflection point – at least in case of the ZnO-EOD – points to a change in the dominant carrier transport mechanism between the low and high voltages [ 57 – 59 ]. At voltages below 2 V, the ZnO-EOD characteristics exhibit a slope of 1.3 suggesting trap-limited space charge limited current.…”

Organic Molecules in All‐Inorganic CsPbIxBr3−xPerovskite Solar Cells: Interface Modifiers or Precursor Additives

“…[ 70 ] In addition, P ‐type conjugated polymer poly [3‐(4‐carboxyl butyl) thiophen‐2,5‐diyl](P3CT) was introduced as the polymer passivation agent on the surface of perovskite film as provided in Figure 5b, which is hole transport layer to replace PEDOT: PSS and PTAA for high performance. [ 71 ] With the formation of the π‐conjugated polythiophene skeleton, P3CT with carboxylic acid groups provides a strong interaction with the undercoordinated Pb 2+ ions at the perovskite surface and grain boundaries. The defect passivation improves device efficiency and the long‐term stability of PSCs.…”

“…b) Schematic illustration of CsPbI 2 Br films by P3CT. Reproduced with permission [71]. Copyright 2021, Wiley-VCH.c) The calculated electrostatic potential distribution of three molecules, and band alignment diagram for the PSC tailored by Bpy.…”

Prepared high quality Cs x FA 1 − x PbI 3 based perovskite solar cells with template‐assisted technique

“…Over the past few years, organic‐inorganic perovskite solar cells (PSCs) have been showing very high potential for photovoltaic applications owing to its fascinating optoelectronic properties 1‐7 . The PSCs have made their mark in the field of energy conversion materials with a boom in power conversion efficiency (PCE) from 3.8% beyond 25% 8‐11 …”

“…Over the past few years, organic-inorganic perovskite solar cells (PSCs) have been showing very high potential for photovoltaic applications owing to its fascinating optoelectronic properties. [1][2][3][4][5][6][7] The PSCs have made their mark in the field of energy conversion materials with a boom in power conversion efficiency (PCE) from 3.8% beyond 25%. [8][9][10][11] The efficiency enhancement of traditional PSCs such as methylammonium lead halide (MAPbX 3 , X = Cl, Br, I) is restricted due to its narrower absorption edge ($780 nm) and short carrier diffusion lengths.…”