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Organic-inorganic perovskite solar cells (PSCs) have achieved an inspiring third-party-certificated power conversion efficiency (PCE) of 25.2%, which is comparable with commercialized silicon (Si) and copper indium gallium selenium solar cells. However, their notorious instability, including their deterioration at elevated temperature, is still a serious issue in commercial applications. This thermal instability can be ascribed to the high volatility and reactivity of organic compounds. As a result, solar cells based on inorganic perovskite materials have drawn tremendous attention, owing to their excellent stability against thermal stress. In the last few years, PSCs based on inorganic perovskite materials have seen an astonishing development. In particular, CsPbI3 and CsPbI2Br PSCs demonstrated outstanding PCEs, exceeding 18% and 16%, respectively. In this review, we systematically discuss the properties of inorganic perovskite materials and the device configuration of inorganic PSCs as well as review the progress in PCE and stability. Encouragingly, all-inorganic PSCs, in which all functional layers are inorganic, provide a feasible approach to overcome the thermal instability issue of traditional organic-inorganic PSCs, leading to new perspectives toward commercial production of PSCs.

A hysteresis loop of minority carrier lifetime vs voltage is found in polystyrenesulfonate (PSS)/Si organic-inorganic hybrid heterojunctions, implying an interfacial memory effect. Capacitance-voltage and conductance-voltage hysteresis loops are observed and reveal a memory window. A switchable interface state, which can be controlled by charge transfer based on an electrochemical oxidation/deoxidation process, is suggested to be responsible for this hysteresis effect. We perform first-principle total-energy calculations on the influence of external electric fields and electrons or holes, which are injected into interface states on the adsorption energy of PSS on Si. It is demonstrated that the dependence of the interface adsorption energy difference on the electric field is the origin of this two-state switching. These results offer a concept of organic-inorganic hybrid interface memory being optically or electrically readable, low-cost, and compatible with the flexible organic electronics.

Light-induced degradation has been identified to be a critical issue for most silicon-based solar cell technologies. This study presents an observation of an opposite light-induced enhancement (LIE) effect in photovoltaic performance in poly(3,4-ethylthiophene):polystyrenesulfonate/n-Si organic-inorganic hybrid solar cells. The reduced density of interface states under light soaking (LS) is found to be responsible for the LIE of the hybrid solar cells. An increased minor carrier lifetime under LS and a switchable photoluminescence intensity while applying a voltage bias are observed, providing evidence for the underlying physical mechanism.

In this work, a magnesium (Mg) thin film with a low work function is introduced to obtain a downward energy band at the rear surface of a hybrid solar cell to achieve the function of a back surface field (BSF) similar to the conventional n-n+ high-low junction, i.e., favouring the majority carrier transport and suppressing minority carrier recombination. The open circuit voltages (Voc) of the hybrid solar cells with the Mg BSF layer achieve a clear improvement over those containing only the conventional metal electrode (e.g., Ag), resulting in an increase in the power conversion efficiency (PCE) of the hybrid solar cells from 9.2% to 12.3%. The Suns-Voc measurement determined using a Sinton tool gives Voc as a function of light intensity and shows that Voc increases linearly with the light intensity for the solar cell with the Mg BSF but increases first and then stabilises for the cells without the Mg BSF. This result is attributed to a difference in back surface recombination, further confirming the effi...

The use of polystyrenesulfonate (PSS) thin films in a high-quality passivation scheme involving the suppression of minority carrier recombination at the silicon surface is presented. PSS has been used as a dispersant for aqueous poly-3,4-ethylenedioxythiophene. In this work, PSS is coated as a form of thin film on a Si surface. A millisecond level minority carrier lifetime on a high resistivity Si wafer is obtained. The film thickness, oxygen content, and relative humidity are found to be important factors affecting the passivation quality. While applied to low resistivity silicon wafers, which are widely used for photovoltaic cell fabrication, this scheme yields relatively shorter lifetime, for example, 2.40 ms on n-type and 2.05 ms on p-type wafers with a resistivity of 1–5 Ω·cm. However, these lifetimes are still high enough to obtain high implied open circuit voltages (Voc) of 708 mV and 697 mV for n-type and p-type wafers, respectively. The formation of oxides at the PSS/Si interface is suggested to ...