We demonstrate reduced charge recombination by formation of an engineered passivating layer, which leads to an enhanced power conversion efficiency of 21%.

We achieved improvement in performance and stability of PSCs by growing 2D perovskite layer on top of 3D perovskite films.

To date, antisolvent treatment has become one of the most important means to fabricate high efficiency perovskite solar cells (PSCs); however, the few reported antisolvents have not been analyzed on a uniform platform, and there is hitherto no clear reasoning in the choice of antisolvents toward high performance PSCs. Here, we study the role of the antisolvents in the nucleation kinetics of perovskite solutions and their residual influence on perovskite crystal growth, film formation, and device performance. Through X-ray diffraction analysis on the complicated double mixed perovskite, we qualitatively evaluate the impact of thermal annealing and antisolvent treatment (A.S.T.) on the phase composition and microstructure of the films. By using miscible antisolvents with high boiling point instead of immiscible low boiling point solvents, we obtain homogeneous and almost pinhole-free perovskite films. When using trifluorotoluene (TFT) to replace toluene and chlorobenzene as a novel antisolvent, we achieve a power conversion efficiency (PCE) of 20.3% under optimized device fabrication conditions with a composite perovskite as active layer. The conclusions from this study should assist in establishing reproducible fabrication processes and finding better antisolvent candidates for perovskite solar cells.

We reveal that 2D/3D interfaces are dynamical in nature which is detrimental for long term perovskite solar cells stability.

The 4,4'-dimethoxydiphenylamine-substituted 9,9'-bifluorenylidene (KR216) hole transporting material has been synthesized using a straightforward two-step procedure from commercially available and inexpensive starting reagents, mimicking the synthetically challenging 9,9'-spirobifluorene moiety of the well-studied spiro-OMeTAD. A power conversion efficiency of 17.8 % has been reached employing a novel HTM in a perovskite solar cells.

In this work, we synthesized novel hole transporting materials (HTMs) and we studied their impact on the stability of perovskite-based solar cells (PSCs). The steady-state maximum power output of devices in working condition was monitored to assess the stability and to predict the lifetime of PSCs prepared with different HTMs. We showed that the HTM has significant impact on the device lifetime and we found that novel silolothiophene linked methoxy triphenylamines (Si-OMeTPA) enable more stable PSCs. We reported Si-OMeTPA based devices with half-life of 6 Khrs, compared to 1 Khrs collected for the state-of-the-art PSCs using spirofluorene linked methoxy triphenylamines (spiro-OMeTAD) as HTM. We demonstrated that such clear improvement is correlated to the superior thermal stability of silolothiophene compared to the spiro linked triphenylamines HTMs. Figure 6. Current-voltage curves of the solar cells collected under AM1.5 simulated sun light.Devices were masked with a metal aperture of 0.16 cm 2 to define the active area. The curves were recorded scanning at 0.01 V s -1 from forward bias (FB) to short circuit condition (SC) and the other way around.

Molecularly engineered novel dopant-free hole-transporting materials for perovskite solar cells (PSCs) combined with mixed-perovskite (FAPbI ) (MAPbBr ) (MA: CH NH , FA: NH=CHNH ) that exhibit an excellent power conversion efficiency of 18.9% under AM 1.5 conditions are investigated. The mobilities of FA-CN, and TPA-CN are determined to be 1.2 × 10 cm V s and 1.1 × 10 cm V s , respectively. Exceptional stability up to 500 h is measured with the PSC based on FA-CN. Additionally, it is found that the maximum power output collected after 1300 h remained 65% of its initial value. This opens up new avenue for efficient and stable PSCs exploring new materials as alternatives to Spiro-OMeTAD.

The morphological, opto-physical and electrical properties of the SnO2layer in perovskite solar cells are investigated.