KEYWORDS: Perovskite, Photovoltaics, Electrodes, Light sources and illumination, Internet of things, Solar cells, Self-assembled monolayers, Portability, Polymers, Nanostructures
We propose unique anodic nanostructures, consisting of hole-transporting polymers and self-assembled monolayers, to fabricate perovskite solar cells. The so-called, self-adaptive transport layer effectively reduced the loss of open circuit voltage and fill factor. The PCE value could reach 19.63% under 1-sun standard illumination condition. More importantly, the device exhibited high PCEs of 33.54% and 38.16% under illumination of indoor light sources at 200 and 2000 lux, respectively. This indoor PCE at 2000 lux is one of the best values for inverted perovskite devices. Furthermore, a very high efficiency of over 40% was also achieved after an optical enhancing layer was applied. Such indoor PCE at 2000 lux is one of the best values for inverted perovskite photovoltaic devices. Finally, the stability of the devices is also evaluated.
Visible light communication (VLC), which utilizes LEDs, promises superior privacy and security and reduced impact on surrounding electronics compared to traditional Wi-Fi. This paper explores the potential of InGaN-based micro-light-emitting diodes (micro-LEDs) in high-speed VLC applications, focusing on yellow-green micro-LEDs with nanoporous distributed Bragg reflector (NP-DBR) and red InGaN micro-LEDs. Yellow-green micro-LEDs achieved a maximum external quantum efficiency (EQE) of 8.7%, bandwidth of 442 MHz, and data rate of 800 Mbit/s, while red micro-LEDs demonstrated an EQE of 5.95%, maximum bandwidth of 424 MHz, and data rate of 800 Mbit/s. The application of four core technologies, including circular devices and electrodes, reduced contact electrode area, atomic layer deposition (ALD) for passivation protection, and multi-chip parallel arrays, enhanced optoelectronic characteristics. This paper also highlights the superior performance of InGaN-based red micro-LEDs with a single quantum well (SQW) structure over double quantum wells (DQWs) for VLC applications. The SQW structure yielded higher maximum EQE, modulation bandwidth, and faster transmission rates, paving the way for the potential of full-color micro-display and high-speed VLC applications.
Because single crystals (SCs) contain less defects, perovskite solar cells (PeSCs) prepared with SCs should ideally exhibit higher efficiencies. Most of the crystallization methods proposed so far, however, require an interfacial layer to modify the surface property of the substrates to facilitate the diffusion of the precursor ions. The resistance of the interfacial layer, which often also serves as charge transport layers, inevitably increases the series resistance of the solar cells, thereby limiting the performance. Herein, we dope the interfacial layer, which is also a hole-transport layer (HTL) in our cells, with p-type organic molecules to reduce their resistances and find the power conversion efficiencies (PCEs) of the single-crystal PeSCs are significantly improved. At the optimal concentration, the PCE is improved to 14.99%; the champion PCE is up to 15.67%. The results indicate that the HTL play an important role in determining the performance of the single-crystal PeSCs.
We have employed ink-jet printing (IJP) technology to fabricate self-positioning microlens arrays (MLAs). The glass substrates were first prepatterned through microcontact printing (µCP) hydrophobic self-assembled monolayers (SAMs) to divide the surface into hydrophobic and hydrophilic regions. After IJP of the hydrophilic prepolymer liquids, the lenses were effectively repelled by the patterned SAMs. We obtained high-quality MLAs having diameters of 75 and 100 µm after polymerization of the prepolymers. The lenses' shapes could be controlled by varying the number of printed droplets.
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