The Main Progress of Perovskite Solar Cells in 2020–2021

Perovskite solar cells (PSCs) emerging as a promising photovoltaic technology with high efficiency and low manufacturing cost have attracted the attention from all over the world. Both the efficiency and stability of PSCs have increased steadily in recent years, and the research on reducing lead leakage and developing eco-friendly lead-free perovskites pushes forward the commercialization of PSCs step by step. This review summarizes the main progress of PSCs in 2020 and 2021 from the aspects of efficiency, stability, perovskite-based tandem devices, and lead-free PSCs. Moreover, a brief discussion on the development of PSC modules and its challenges toward practical application is provided

An efficient hole transport material composite based on poly(3-hexylthiophene) and bamboo-structured carbon nanotubes for high performance perovskite solar cells

In this work, we have developed a new efficient hole transport material (HTM) composite based on poly(3- hexylthiophene) (P3HT) and bamboo-structured carbon nanotubes (BCNs) for CH3NH3PbI3 (MAPbI3) based perovskite solar cells. Compared to pristine P3HT, it is found that the crystallinity of P3HT was significantly improved by addition of BCNs, which led to over one order of magnitude higher conductivity for the composite containing 1–2 wt% BCNs in P3HT. In the meantime, the interfacial charge transfer between the MAPbI3 light absorbing layer and the HTM composite layer based on P3HT/BCNs was two-fold faster than pristine P3HT. More importantly, the HTM film with a superior morphological structure consisting of closely compact large grains was achieved with the composite containing 1 wt% BCNs in P3HT. The study by electrochemical impedance spectroscopy has confirmed that the electron recombination in the solar cells was reduced nearly ten-fold with the addition of 1 wt% carbon nanotubes in the HTM composite. Owing to the superior HTM film morphology and the significantly reduced charge recombination, the energy conversion efficiency of the perovskite solar cells increased from 3.6% for pristine P3HT to 8.3% for P3HT/(1 wt% BCNs) with a significantly enhanced open circuit voltage (Voc) and fill factor (FF). The findings of this work are important for development of new HTM for high performance perovskite solar cells

The light attracting effect of pyridine derivatives based quasi-solid electrolyte in dye-sensitized solar cell

The pyridine derivatives are added into acetonitrile based electrolyte to establish framework, then form the quasi solid electrolyte. The ion diffusion of cetylpyridinium chloride and cetylpyridinium bromide based electrolytes is enhanced comparing with the ion diffusion of reference acetonitrile electrolyte. The ordered structure of cetylpyridinuium chloride quasi solid electrolyte has been observed by SEM images. Light scattering effect of cetylpyridinuium chloride quasi solid electrolyte is evidenced by the larger resulted by transmitted and scattered spectra. The light harvesting efficiency of device based on C16Cl is much higher than acetonitrile based device. The cell efficiency of C16Cl and C16Br based device are 5.72% and 6.02%, which are 41% and 48% higher than acetonitrile liquid electrolyte based device. The C16I based device produces low cell efficiency 2.06%, which is 49% decrease compare to the blank device due to the limitation of iodide-triodide transportation in the iodide framework

Photo-response of Two-Dimensional Ruddlesden-Popper Perovskite Films for Photovoltaics

Two-dimensional (2D) Ruddlesden-Popper (RP) perovskites have emerged as a prospective candidate to address the instability issues of traditional perovskite solar cells. However, the mechanisms of charge carrier transport of 2D perovskite films obtained by the solution process still remain elusive. In this work, we proposed a novel characterization technique based on the Kelvin probe force microscopy (KPFM) to investigate the micro-scale morphology and surface potential (SP) of the BA2MA3Pb4I13 films. In additionally, a Xenon laser source was adopted to realize the in-situ scanning of the light response of the perovskite film. The obvious increase in surface potential values in the same scanning area before and after white light illumination indicated the emergence of photo-generated charge carriers. Based on the unique photophysical properties and form formation features of the hot-cast BA2MA3Pb4I13 films, we fabricated the 2D perovskite solar cells (PSCs) with an efficiency of 10.95%. As a result, the in-situ KPFM is capable to serve as an effective approach to investigating the charge carrier behaviors in the 2D perovskites for photovoltaic applications

Photo-response of Two-Dimensional Ruddlesden-Popper Perovskite Films for Photovoltaics

Two-dimensional (2D) Ruddlesden-Popper (RP) perovskites have emerged as a prospective candidate to address the instability issues of traditional perovskite solar cells. However, the mechanisms of charge carrier transport of 2D perovskite films obtained by the solution process still remain elusive. In this work, we proposed a novel characterization technique based on the Kelvin probe force microscopy (KPFM) to investigate the micro-scale morphology and surface potential (SP) of the BA2MA3Pb4I13 films. In additionally, a Xenon laser source was adopted to realize the in-situ scanning of the light response of the perovskite film. The obvious increase in surface potential values in the same scanning area before and after white light illumination indicated the emergence of photo-generated charge carriers. Based on the unique photophysical properties and form formation features of the hot-cast BA2MA3Pb4I13 films, we fabricated the 2D perovskite solar cells (PSCs) with an efficiency of 10.95%. As a result, the in-situ KPFM is capable to serve as an effective approach to investigating the charge carrier behaviors in the 2D perovskites for photovoltaic applications.</jats:p

Surface modification of TiO2 by an ionic liquid electrolyte in dye-sensitized solar cells using a molecular insulator

DMImBS is used as a novel additive in dye-sensitized solar cells to restrain the electron recombination and intercalation of Li+.</p

Precisely controlled synthesis of high quality kesterite Cu<SUB>2</SUB>ZnSnS<SUB>4</SUB> thin film via co-electrodeposited CuZnSn alloy film

In this work, a facile co-electrodeposition method was used to fabricate CuZnSn alloy films where the content of copper, zinc and tin could be precisely controlled through manipulating the mass transfer process in the electrochemical deposition. By finely tuning the concentration of the cations of Cu2+, Zn2+ and Sn2+ in the electrochemical bath solution, uniform CuZnSn film with desired composition of copper poor and zinc rich was made. Sulphurisation of the CuZnSn alloy film led to the formation of compact and large grains Cu2ZnSnS4 thin film absorber with an optimum composition of Cu/(Zn+Sn)≈0.8, Zn/Sn≈1.2. Both SEM morphology and EDS mapping results confirmed the uniformity of the CuZnSn and Cu2ZnSnS4 films and the homogeneous distribution of Cu, Zn, Sn and S elements in the bulk films. The XRD and Raman measurements indicated that the synthesized Cu2ZnSnS4 film was kesterite phase without impurities detected. Photoelectrochemical tests were carried out to evaluate the CZTS film’s photocurrent response under illumination of green light