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In this paper, we propose an ultrahigh‐resolution organic light‐emitting diodes (OLEDs) pixels patterned by conventional photolithography through by incorporating silicone into phosphorescent small‐molecule networks. This silicone‐integrated phosphorescent organic light‐emitting diode (SI‐phOLED), in which silicone molecules are homogeneously crosslinked with small‐molecule light‐emitting materials, can effortlessly achieve to 3,000 PPI ultrahigh‐resolution patterns using the photolithography process. [ABSTRACT FROM AUTHOR]

Conjugated polymers based on cyclopentadithiophene (CPDT) moieties are widely used in optoelectronics applications but rarely in field‐effect transistors (FETs). This is due to the steric hindrance at the tetrahedral center of the CPDT core, which is a critical problem requiring resolution without diminishing the polymer crystallinity and solubility. A bulky CPDT‐based high‐mobility copolymers are synthesized here, which shows excellent π–π stacking in the film states with good solubility. The addition of bulky ethylhexyl side chains to CPDT does not interfere with the molecular ordering and promotes the intercalation of linear alkyl chains on the co‐monomeric units. The resulting polymer forms bimodal packing structures with strong lamellar ordering and π–π interactions. Furthermore, the free volume generated by the bulky ethylhexyl side chains allows for a small amount of fullerene additive to be contained in the film state without interfering with the molecular ordering, leading to enhanced on/off ratios and hole mobilities of the resulting FETs. As a result, promising hole mobilities of up to 1.08–1.64 cm2 V−1 s−1 are achieved with the optimized FETs, which are the highest mobilities reported for CPDT‐based conjugated polymers containing branched alkyl side chains. [ABSTRACT FROM AUTHOR]

Colloidal quantum dot (CQD) photodetectors (PDs) are developed. The on/off current ratio is improved by applying organic cathode buffer layers (CBLs), such as polyethylenimine ethoxylated (PEIE) and polyethylene glycol (PEG). The on‐current of CQD‐PDs (QPDs) is increased by the decreased work function of ZnO/CBLs via forming a permanent dipole moment at the interface of ZnO and CBLs. The off‐current is significantly decreased by the improved interfacial morphology via softening the ZnO surfaces. In the photoconductive mode for the fast response time of a signal, PEG‐ and PEIE‐treated QPDs exhibit improved photodetecting properties. Notably, the performance of PEG‐treated QPDs fluctuates less at the concentration of the prepared CBL solution. The utilization of environmentally friendly and cheap PEG as CBLs is attractive for QPDs. The organic CBL is highly effective for QPDs to improve both on‐ and off‐current characteristics. Organic cathode buffer layers (CBLs) are applied in PbS‐based quantum‐dot photodetectors (QPDs) to increase the on/off current ratio of the devices. The off‐current of QPDs is significantly decreased and the on‐current is increased in the presence of a CBL via improving the interfacial morphology and tuning the work function of the ZnO layer. [ABSTRACT FROM AUTHOR]

Among the solution-processed devices, perovskite solar cells (PSCs) exhibit the highest power conversion efficiency (PCE) of over 25%; tremendous efforts are being undertaken to improve their stability. Recently, all-inorganic CsPbI 2 Br-based PSCs were reported to exhibit a significantly improved device stability, with a promising PCE of up to 16.79%. In this study, we report stable all-inorganic PSCs by incorporating novel dopant-free hole-transporting materials (HTMs). The synthesis strategy of the newly synthesized polymeric HTMs was similar to that of 2,2',7,7'-tetrakis( N , N -di- p -methoxyphenylamine)-9,9'-spirobifluorene (spiro-OMeTAD), with the exception that they were designed to exhibit dopant-free characteristics. In particular, their polymeric backbone structure was significantly simpler than that of spiro-OMeTADs, and they were easily synthesized in two steps from commercially available chemicals, with an overall yield of ∼50%. The cost of synthesis at the laboratory scale was calculated to be at least 2.4 times cheaper than that of spiro-OMeTADs. The PCE of dopant-free HTM-based PSCs was 11.01%, which is 1.5 times higher than that of the dopant-free spiro-OMeTAD-based devices (7.52%) and comparable to that of the doped spiro-OMeTAD-based devices (12.22%). Notably, the stability of the device based on our dopant-free HTM to atmospheric oxygen and moisture as well as heat and light irradiation was superior to that of devices based on doped and dopant-free spiro-OMeTAD HTMs. On consideration of the synthesis cost, device efficiency, and device stability, our dopant-free HTM is highly promising for all-inorganic PSCs.