Hole/Electron Transporting Materials for Nonfullerene Organic Solar Cells

Abstract

Nonfullerene acceptor based organic solar cells (NF‐OSCs) have witnessed rapid progress over the past few years owing to the intensive research efforts on novel electron donor and nonfullerene acceptor (NFA) materials, interfacial engineering, and device processing techniques. Interfacial layers including electron transporting layers (ETL) and hole transporting layers (HTLs) are crucially important in the OSCs for facilitating electron and hole extraction from the photoactive blend to the respective electrodes. In this review, the lates progress in both ETLs and HTLs for the currently prevailing NF‐OSCs are discussed, in which the ETLs are summarized from the categories of metal oxides, metal chelates, non‐conjugated electrolytes and conjugated electrolytes, and the HTLs are summarized from the categories of inorganic and organic materials. In addition, some bifunctional interlayer materials served as both ETLs and HTLs are also introduced. Finally, the prospects of ETL/HTL materials for NF‐OSCs are provided.

Enhancing the performance of organic solar cells by using PDINN-doped PEDOT:PSS as the hole transport layer

“…6–15 Interfacial transport layers, including hole transport layers (HTLs) and electron transport layers (ETLs), are crucially important in OSCs for facilitating hole and electron extraction from the active layer to the anode and cathode, respectively. 16–18 Currently, almost all non-fullerene-based high-efficiency OSCs use poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) as the HTL. PEDOT:PSS has the merits of high optical transparency, low-temperature solution processability, suitable work function (WF) and good thermal/electrochemical stability, so it dominates the choice for HTLs in the conventional device structure of OSCs.…”

CPE-Na-Based Hole Transport Layers for Improving the Stability in Nonfullerene Organic Solar Cells: A Comprehensive Study

“…The hole charge extraction, on the other hand, is often done with poly(3,4-ethylenedioxythiophene) polystyrenesulfonate (PEDOT:PSS), which is not only one of the most frequently used hole transport materials 26,27 but also a successful one with several PCE reports above 19%. 8−10 Nevertheless, the hygroscopic nature of PEDOT:PSS hinders the long-term stability of the device, 28,29 and the acidity of PSS can lead to corrosion of some other layers in the cell, particularly the transparent conducting oxide contacts.…”

Decreasing the Molecular Polarity of Naphthalimide by a π-Bridge Strategy as Cathode Interlayers to Enable High-Efficient Electron Transfer in Organic Solar Cells

“…Over the past decades, organic solar cells (OSCs) have emerged as one of the most promising photovoltaic technologies due to their semitransparency, mechanically flexibility, light weight, and solution processability. − The advancement of polymer donors and small-molecule acceptors has boosted the certified power conversion efficiency (PCE) of OSCs to over 19%. − The development of photovoltaic materials plays a crucial role in achieving breakthroughs in performance. , Interface engineering, including cathode interfacial layers (CILs), also plays a significant role in promoting carrier transfer and extraction for OSCs. − …”