Roadmap on commercialization of metal halide perovskite photovoltaics

Perovskite solar cells (PSCs) represent one of the most promising emerging photovoltaic technologies due to their high power conversion efficiency. However, despite the huge progress made not only in terms of the efficiency achieved, but also fundamental understanding of the relevant physics of the devices and issues which affect their efficiency and stability, there are still unresolved problems and obstacles on the path toward commercialization of this promising technology. In this roadmap, we aim to provide a concise and up to date summary of outstanding issues and challenges, and the progress made toward addressing these issues. While the format of this article is not meant to be a comprehensive review of the topic, it provides a collection of the viewpoints of the experts in the field, which covers a broad range of topics related to PSC commercialization, including those relevant for manufacturing (scaling up, different types of devices), operation and stability (various factors), and environmental issues (in particular the use of lead). We hope that the article will provide a useful resource for researchers in the field and that it will facilitate discussions and move forward toward addressing the outstanding challenges in this fast-developing field

Demonstration of laser-produced neutron diagnostic by radiative capture gamma-rays

We report a new scenario of time-of-flight (TOF) technique in which fast neutrons and delayed gamma-ray signals were both recorded in a millisecond time window in harsh environments induced by high-intensity lasers. The delayed gamma signals, arriving far later than the original fast neutron and often being ignored previously, were identified to be the results of radiative captures of thermalized neutrons. The linear correlation between gamma photon number and the fast neutron yield shows that these delayed gamma events can be employed for neutron diagnosis. This method can reduce the detecting efficiency dropping problem caused by prompt high-flux gamma radiation, and provides a new way for neutron diagnosing in high-intensity laser-target interaction experiments

Manipulation of Crystallization Kinetics for Perovskite Photovoltaics Prepared Using Two-Step Method

Two-step fabricated perovskite solar cells have attracted considerable attention because of their good reproducibility and controllable crystallization during production. Optimizing the quality of perovskite films plays a decisive role in realizing superb performance via a two-step method. Many breakthroughs have been achieved to obtain high-quality film from the perspective of manipulating crystallization kinetics in the two-step preparation process, which promotes the rapid development of perovskite photovoltaics. Therefore, focusing on the crystallization process in the two-step preparation process can provide a reliable basis for optimizing the performance of two-step devices. In this review, recent progress on regulating the crystallization process for two-step PSCs is systematically reviewed. Firstly, a specific description and discussion are provided on the crystallization process of perovskite in different two-step methods, including spin-coating, immersion and evaporation. Next, to obtain high-quality perovskite film via these two-step methods, current strategies of additive engineering, composition engineering, and solvent engineering for regulating the crystallization process for two-step perovskite are classified and investigated. Lastly, the challenges which hindering the performance of the two-step perovskite photovoltaics and an outlook toward further developments are proposed

Manipulation of Crystallization Kinetics for Perovskite Photovoltaics Prepared Using Two-Step Method

Two-step fabricated perovskite solar cells have attracted considerable attention because of their good reproducibility and controllable crystallization during production. Optimizing the quality of perovskite films plays a decisive role in realizing superb performance via a two-step method. Many breakthroughs have been achieved to obtain high-quality film from the perspective of manipulating crystallization kinetics in the two-step preparation process, which promotes the rapid development of perovskite photovoltaics. Therefore, focusing on the crystallization process in the two-step preparation process can provide a reliable basis for optimizing the performance of two-step devices. In this review, recent progress on regulating the crystallization process for two-step PSCs is systematically reviewed. Firstly, a specific description and discussion are provided on the crystallization process of perovskite in different two-step methods, including spin-coating, immersion and evaporation. Next, to obtain high-quality perovskite film via these two-step methods, current strategies of additive engineering, composition engineering, and solvent engineering for regulating the crystallization process for two-step perovskite are classified and investigated. Lastly, the challenges which hindering the performance of the two-step perovskite photovoltaics and an outlook toward further developments are proposed

MIXED DIMENSIONAL PEROVSKITES HETEROSTRUCTURE FOR HIGHLYEFFICIENT AND STABLE PEROVSKITE SOLAR CELLS

Heterojunctions constructed upon multidimensional perovskites (1D/3D or 2D/3D) has emerged as an effective approach to improve the photovoltaic performance and stability of perovskite solar cells (PSCs). Herein, 1D trimethyl sulfonium lead triiodide (Me3SPbI3) 1D Me3SPbI3 nanoarrays are successfully synthesized via a two-step method in aqueous condition, which reflects excellent water resistivity and environmental stability. By incorporating this 1D Me3SPbI3 into lead halide 3D perovskites, heterostructural 1D/3D perovskite photoactive layer with improved morphology, crystallinity, enhanced photoluminescence lifetime, and reduced carrier recombination in comparison to its 3D counterpart is obtained. Moreover, an efficient and stable 1D/3D PSCs with power conversion efficiency (PCE) of 22.06% by using this 1D/3D perovskite are demonstrated. It noticeably maintained 97% of their initial efficiency after 1000 h storage under ambient condition (RH≈50%) without encapsulation. Our study opens up the design protocol for the development of next-generation highly efficient and stable perovskite solar cells

Novel photoelectric material of perovskite-like (CH3)(3)SPbI3 nanorod arrays with high stability

Organometallic halide perovskite materials make great achievements in optoelectronic fields, especially in solar cells, in which the organic cations contain amine components. However, the amine with N-H bonds is easily hydrolyzed with moisture in the air, weakening the perovskite materials stability. It is desirable to develop other non-amine stable perovskite materials. In this work, sulfur-based perovskite-like (CH3)(3)SPbI3 nanorod arrays were fabricated by a solution-processed method, which can be indexed hexagonal crystal structure in the space group P63mc. The binding force is exceptionally strong between the non-amine (CH3)(3)S+ and [PbI6](4-) octahedral, leading to high stability of (CH3)(3)SPbI3. The (CH3)(3)SPbI3 nanorod arrays can keep the morphology and crystal structure in an ambient atmosphere over 60 days. In addition, the (CH3)(3)SPbI3 nanorod arrays can offer direct charge transfer channels, which show excellent optoelectronic properties. The (CH3)(3)SPbI3 nanorod arrays-based solar cells with VOx hole transfer layers achieved a power conversion efficiency of 2.07% with negligible hysteresis. And the (CH3)(3)SPbI3 nanorod arrays were also effectively applied in photodetectors with interdigitated gold electrodes. This work demonstrates that sulfur-based perovskite-like (CH3)(3)SPbI3 is a novel promising stable compound with great potential for practical optoelectronic applications. (C) 2020 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by ELSEVIER B.V. and Science Press. All rights reserved

Recent progress with one-dimensional metal halide perovskites: from rational synthesis to optoelectronic applications

Abstract Metal halide perovskites can be readily synthesized, they exhibit tunable physical properties and excellent performance, and they are heavily studied optoelectronic materials. Compared to the typical three-dimensional perovskites, morphological-level one-dimensional (1D) nanostructures enable charge transport and photon propagation with low exciton binding energies and long charge-carrier diffusion lengths, while molecular-level 1D nanostructures exhibit good compositional and structural flexibilities, highly tunable bandgaps, strong quantum confinement effects, and excellent ambient stabilities. The 1D natures of these emerging halide perovskites enhance the performance of optoelectronic devices. Herein, we highlight recent progress realized in the syntheses and characterizations of both morphological- and molecular-level 1D halide perovskites with tunable structures, compositions, and properties, as well as their photovoltaic, light-emission, and photodetection applications. In addition, current challenges, future prospects, and promising research directions are discussed to provide guidance in advancing the field of 1D perovskites