The ORCID identification number(s) for the author(s) of this article can be found under https://doi.org/10.1002/smtd.201900569.Perovskite solar cells (PSCs) have achieved 25.2% of their certified efficiency and emerged as up-and-coming energy-harvesting candidates owing to their superior properties. However, perovskite films are mainly polycrystalline films, and thus, the formation of grain boundaries (GBs) is inevitable. Since GBs have numerous defect sites that provide a channel for ion migration, reducing GBs is highly significant for achieving high efficiency and long-term stability of PSCs. To this end, researchers have made efforts to produce a large crystal-based perovskite film with reduced GBs. In this study, various methods that decrease GBs and enhance the morphology of perovskites are summarized and categorized into methodology-and material-based approaches. Furthermore, a future research direction to produce high-quality and large grain-based perovskite film is also proposed.

With the unprecedented development in perovskite solar cells (PSCs), various interlayers have been investigated. Interlayers have diverse roles in shifting the energy levels, attracting and extracting charges, and passivating surface...

Organic photovoltaics (OPVs) are a promising next-generation photovoltaic technology with great potential for wearable and transparent device applications. Over the past decades, remarkable advances in device efficiency close to 20 % have been made for bulk heterojunction (BHJ)-based OPV devices with long-term stability, and room for further improvements still exists. In recent years, ancillary components have been demonstrated as effective in improving the photovoltaic performance of OPVs by controlling the optoelectronic and morphological properties of BHJ blends. Herein, an updated understanding of polymer-based blend OPVs is provided, and the role and impact of ancillary components in various blend systems are categorized and discussed. Lastly, a strategic perspective on the ancillary components of blend-based OPVs for commercialization is provided.

Perovskite quantum dots (PQDs) have been considered promising and effective photovoltaic absorber due to their superior optoelectronic properties and inherent material merits combining perovskites and QDs. However, they exhibit low moisture stability at room humidity (20–30%) owing to many surface defect sites generated by inefficient ligand exchange process. These surface traps must be re-passivated to improve both charge transport ability and moisture stability. To address this issue, PQD-organic semiconductor hybrid solar cells with suitable electrical properties and functional groups might dramatically improve the charge extraction and defect passivation. Conventional organic semiconductors are typically low-dimensional (1D and 2D) and prone to excessive self-aggregation, which limits chemical interaction with PQDs. In this work, we designed a new 3D star-shaped semiconducting material (Star-TrCN) to enhance the compatibility with PQDs. The robust bonding with Star-TrCN and PQDs is demonstrated by theoretical modeling and experimental validation. The Star-TrCN-PQD hybrid films show improved cubic-phase stability of CsPbI3-PQDs via reduced surface trap states and suppressed moisture penetration. As a result, the resultant devices not only achieve remarkable device stability over 1000 h at 20–30% relative humidity, but also boost power conversion efficiency up to 16.0% via forming a cascade energy band structure.