Constructing Nanostructured Donor/Acceptor Bulk Heterojunctions via Interfacial Templates for Efficient Organic Photovoltaics

Efficient and Stable Perovskite Solar Cells Using Low-Cost Aniline-Based Enamine Hole-Transporting Materials

Metal-halide perovskites offer great potential to realize low-cost and flexible next-generation solar cells. Low-temperature-processed organic hole-transporting layers play an important role in advancing device efficiencies and stabilities. Inexpensive and stable hole-transporting materials (HTMs) are highly desirable toward the scaling up of perovskite solar cells (PSCs). Here, a new group of aniline-based enamine HTMs obtained via a one-step synthesis procedure is reported, without using a transition metal catalyst, from very common and inexpensive aniline precursors. This results in a material cost reduction to less than 1/5 of that for the archetypal spiro-OMeTAD. PSCs using an enamine V1091 HTM exhibit a champion power conversion efficiency of over 20%. Importantly, the unsealed devices with V1091 retain 96% of their original efficiency after storage in ambient air, with a relative humidity of 45% for over 800 h, while the devices fabricated using spiro-OMeTAD dropped down to 42% of their original efficiency after aging. Additionally, these materials can be processed via both solution and vacuum processes, which is believed to open up new possibilities for interlayers used in large-area all perovskite tandem cells, as well as many other optoelectronic device applications.

Simultaneous Improvement of Efficiency and Lifetime of Quantum Dot Light-Emitting Diodes with a Bilayer Hole Injection Layer Consisting of PEDOT:PSS and Solution-Processed WO3

Even though chemically stable metal oxides (MOs), as substitutes for poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS), have been successfully adopted for improving device stability in solution-processed quantum dot light-emitting diodes (QLEDs), the efficiencies of QLEDs are at a relatively low level. In this work, a novel architecture of QLEDs has been introduced, in which inorganic/organic bilayer hole injection layers (HILs) were delicately designed by inserting an amorphous WO₃ interlayer between PEDOT:PSS and the indium tin oxide anode. As a result, the efficiency and operational lifetime of QLEDs were improved simultaneously. The results show that the novel architecture QLEDs relative to conventional PEDOT:PSS-based QLEDs have an enhanced external quantum efficiency by a factor of 50%, increasing from 8.31 to 12.47%, meanwhile exhibit a relatively long operational lifetime (12 551 h) and high maximum brightness (>40 000 cd m^-2) resulting from a better pathway for hole injection with staircase energy-level alignment of the HILs and reduction of surface roughness. Our results demonstrate that the novel architecture QLEDs using bilayer MO/PEDOT:PSS HILs can achieve long operational lifetime without sacrificing efficiency.