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[Display omitted] • Two pyrrolo[3,2-b] pyrrole core (PP) based small molecular HTMs is peported. • An impressive efficiency of 24.3% is achieved with HTM FPPY. • FPPY-based PSC exhibits improved stability than reference device, Hole-transport materials (HTM) play a crucial role in functioning perovskite solar cells (PSCs). In this research, we develop and synthesize two pyrrolo[3,2-b] pyrrole core (PP) based small molecular HTMs, FPPY and BPPY with/without (w/wo) fluorine (F) substitution on PP core that connected to the carbazole diphenylamine peripheral end groups, respectively. The F-substituted fused electron-rich pyrrole ring core greatly impacts FPPY molecular surface charge distribution, which contributes to higher hole extraction properties and excellent band alignment. Finally, FPPY -based PSCs obtain a best power conversion efficiency (PCE) of 24.3 %, significantly higher than BPPY (20.1 %). After aging 2000 h at ambient condition (25 °C, 30–50 % RH), the FPPY -based device still keeps over 87 % of its initial PCE. [ABSTRACT FROM AUTHOR]

[Display omitted] • Butylammonium iodide was used to modify CsPbI 2 Br perovskite films as additive. • A high-quality CsPbI 2 Br film was obtained, resulting in an enhanced efficiency with a noticeable increase in V oc and J sc. • The butylammonium cation effectively suppressed charge recombination losses and facilitated efficient charge transfer. • Butylammonium-based CsPbI 2 Br PSCs demonstrated improved long-term stability. Defects in all inorganic perovskite films currently limit the efficiency and long-term stability of perovskite solar cells (PSCs). In this study, we utilized the n-butylammonium cation as an additive to enhance the performance of PSCs. By incorporating n-butylammonium iodide, modifications in crystallization were achieved, resulting in high-quality CsPbI 2 Br perovskite films with larger grain sizes. As a result, the inverted PSCs with 1 mol percent additive exhibited an enhanced power conversion efficiency (PCE) of up to 13.0%, compared to the control PCE of 10.8%. The improvement can be primarily attributed to reduced trap states and suppressed charge recombination within the inverted PSCs. Furthermore, the hydrophobic nature of the additive noticeably improved the long-term stability of CsPbI 2 Br PSCs. [ABSTRACT FROM AUTHOR]

The performance of perovskite solar cells (PSCs) is one of the key factors influencing their industrialization and market competitiveness. In this paper, post-annealing treatment, which is an effective and simple method, was used to enhance the performance of PSCs. PSCs with different hole transport layer (HTL) were prepared, and the effect of post-annealing treatment on the performance of PSCs was investigated. The results showed that post-annealing treatment could enhance the carrier extraction ability of HTL, reduce the defects in the perovskite layer, decrease non-radiative recombination, and effectively improve the device performance when PTAA was included in the HTL. After annealing treatment, it was found that the PCSs with NiO x /PTAA as the transport layer, the champion device of PSCs can achieve a PCE of 21.21 %. Compared to devices using only NiO x and PPAA as hole transport layers, the PCE increased by 36.9 % and 3 %, respectively. Meanwhile, when using NiO x /PTAA as the transport layer, compared to devices without annealing treatment, the PCE increased from 17.95 % to 21.21 %, resulting in an 18.2 % enhancement. The obtained results in this work can provide an important theoretical basis for researchers to understand the physical mechanism of post-annealing treatment on device performance and fabricate perovskite solar cells with high-performance. [ABSTRACT FROM AUTHOR]

[Display omitted] • Standard-structured wide-bandgap PSCs were fabricated with the ETL of PEDOT:PSS/PEI. • An average PCE of 18.6 % was obtained for the PSCs using PEDOT:PSS/PEI. • The coating of PEI improved the quality of perovskite film. • PCE degradation was suppressed from 29.7 % to 15.6 %. We used work-function-tuned poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) as the electron-transport layer for wide-bandgap (1.74 eV) perovskite solar cells (PSCs). With the coating of polyethylenimine, the work function of PEDOT:PSS was modified from −5.03 to −4.05 eV, which enabled efficient electron transportation from perovskite absorber to cathode. With this technique, the standard-structured n -i-p PSCs showed an average power-conversion-efficiency (PCE) of 18.6 %, which is higher than that (17.5 %) of inverted PSCs with PEDOT:PSS as the hole-transport layer. Moreover, the long-term stability of the PSCs was enhanced with the PCE degradation significantly suppressed from 29.7 % to 15.6 % after a 10 days' measurement in ambient. [ABSTRACT FROM AUTHOR]