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Light-emitting transistors (LETs) uniquely combine the electroluminescent features of LEDs with the switching capabilities of field-effect transistors, offering promising applications in advanced display technology, lighting, electrically pumped lasers, and optical communication systems. This study reports on the fabrication and performance of perovskite light-emitting transistors (PeLETs) using solution-processed CsPbBr3 thin films, enhanced with phenethylammonium bromide (PEABr) and polyethylene oxide (PEO) to create a multi-dimensional mixed phase with a quantum well structure, characterized by a reduced presence of low-dimensional phases and an increased proportion of high-dimensional phases, thereby enhancing exciton recombination efficiency. The incorporation of high-mobility zinc tin oxide (ZTO) films as channel and electron transport layers is investigated. Direct contact between the perovskite and ZTO layers initially leads to an increased off-state current and degraded electrical characteristics of ZTO field-effect transistors (FETs). However, introducing polyvinylpyrrolidone (PVP) as a modification layer significantly improves these characteristics, resulting in a more uniform electric field distribution and consistent surface emission under coplanar electrodes. The optimized PeLET demonstrates mobility of 0.73 cm2 V−1 s−1 and an on–off ratio exceeding 105. High-purity green light emission at 514 nm with a narrow full-width at half-maximum (FWHM) of 19.97 nm is achieved, showcasing the potential of PeLETs in various optoelectronic applications. [ABSTRACT FROM AUTHOR]

Micro–nano organic–inorganic hybrid lead halide perovskites have become some of the most promising materials for optoelectronic applications due to their excellent photoelectric properties. The micro–nano scale laser device made using these materials would be an ideal light source for integrated photonics. The preparation methods of perovskite crystals grown via solution processing have improved a lot, but it is difficult to prepare discrete Fabry–Pérot (F–P) mode optical resonators with high-quality factor and small volume on the substrates due to random nucleation and excessive nucleation points. Hence, we used silver nanowires to induce the crystallization of perovskite crystallites, forming a perovskite/silver coupling structure and achieving an efficient laser. The directional distribution matrix of perovskite crystallites was obtained by adjusting the directional distribution of silver nanowires by using a controllable pulling method. By adjusting the concentration of the perovskite precursor solution, the aspect ratio of the crystallized perovskite microcrystals can be regulated, thus achieving the resonance modes of different perovskite microcavities. The results would open up an alternative approach to achieve controllable growth of perovskite crystallites. [ABSTRACT FROM AUTHOR]

Self-powered photodetectors have been attracting more and more attention due to the energy shortage issues around the world. As a type of layered van der Waals material, NiPS3 has garnered much attention in the realms of optoelectronics. In order to excavate the possible self-powered potential of this material, we utilized the asymmetric electrode contact design in the device structure of a NiPS3-based photodetector. Photoelectric characterization of the device presented a broadband spectral detection range from 254 nm to 1020 nm. The device showed a zero-bias photoelectric response with responsivity and detectivity of 2.3 mA W−1 and 6.2 × 109 Jones, respectively. Moreover, this photodetector exhibited a response time of less than 40 ms for both rising and decay times and low dark current (∼pA). The self-powered phenomenon is possibly attributed to the unbalanced Schottky barriers of the two electrode contacts. This study provides a potential route for van der Waals material-based photoelectric devices applied in wearable photoelectronic devices and green energy economy. [ABSTRACT FROM AUTHOR]

As promising candidates in optoelectronics, transition metal thiophosphates (MTPs) have attracted intensive research interest due to their strong light absorption and tunable bandgaps. As a member of the MTP family, SnP2S6 has demonstrated significant potential for application in photodetectors (PDs). Here, we report a SnP2S6-based metal–semiconductor–metal (MSM) photodetector with asymmetric electrode contacts. The device demonstrated a responsivity of 146.82 mA W−1 and a detectivity of 8.0 × 1010 Jones in the visible light region. Moreover, it showed self-powered behavior at zero bias voltage with an ultra-low dark current, fast response speed, high responsivity and high detectivity. The self-powered response current of the device could be attributed to the net current generated by the unbalanced energy barriers of the two asymmetric Schottky contacts between the crystal and the gold electrodes. This work provides a possible way for the application of SnP2S6-based PDs in portable energy saving devices. [ABSTRACT FROM AUTHOR]

Cu-based halide perovskites have attracted extensive attention in the optoelectronic field owing to their non-toxic nature and excellent stability. Nevertheless, the growth mechanism of Cu-based halide perovskite nanocrystals (NCs) remains unclear, and the size and uniformity of NCs are difficult to control, which seriously hinders the development of these materials. Herein, a facile hot-injection method was applied to control the size and uniformity of blue-emitting (450 nm) Cs3Cu2I5 NCs. The dimensions of Cu-based perovskites were tuned from zero-dimensional NCs to one-dimensional nanorods. Additionally, the sizes of Cs3Cu2I5 NCs could be tuned from 22.1 ± 1.5 to 8.9 ± 1.1 nm by varying the reaction temperature and the dosage of cesium oleate, which is also extended to tune the size of Cs3Cu2X5 (X = Br and Cl) NCs. Interestingly, the photoluminescence (PL) maximum at 450 nm was almost unchanged with the size tuning, indicating that PL is from the radiation recombination of self-trap exciton emission. Moreover, the phase transition temperature of Cs3Cu2X5 NCs was regulated by varying the size, where a small size is beneficial to the decrease of the phase transition temperature. As a demonstration, the different-sized Cs3Cu2X5 NCs exhibited a size-dependent temperature response, and the response time became shorter as the size decreased. The temperature response of the small-sized Cs3Cu2X5 NCs could be decreased to only 15 s, which is better than that of their counterparts reported previously. This work may deepen the understanding of the size-dependent phase transition process in Cu-based perovskite NCs. [ABSTRACT FROM AUTHOR]

p–n Junctions have been widely used in the construction of high-performance TiO2 ultraviolet photoelectric detector devices, especially NiO/TiO2 heterostructures. In this work, two devices with different structures were constructed to investigate the effects of the growth of NiO above (S-TN) and below (D-NT) the TiO2 array on the device performance, and the D-NT device showed better performance. The D-NT device exhibited a lower dark current, with a decrease of approximately an order of magnitude compared with S-TN PD and TiO2 nanoarray (NA) PDs. The D-NT heterojunction device demonstrated a large on–off ratio of 5.4 × 104, a high detection sensitivity of 1.44 × 1014 Jones, and a fast photoresponse time of 2 s under UV light illumination. Interestingly, the D-NT device also displayed self-powered performance, and its photoresponse time was 0.1 s. The dense and uniform NiO film deposited on the FTO substrate not only forms a built-in potential field with the TiO2 NAs, but it also provides greater uniformity and stability to this built-in potential field compared to a NiO layer spin-coated on TiO2 NAs, which may be the main reason for the high performance of the D-NT photodetector. The device in which NiO was grown below the TiO2 array provides a fundamental basis for the future development of all-solid-state photodetectors. [ABSTRACT FROM AUTHOR]

Herein, we demonstrated a seed-mediated growth method for the synthesis of ternary AgInS2 (AIS) and quaternary Ag–In–Zn–S (AIZS) nanocrystals (NCs) by means of a partial cation exchange with In3+ and Zn2+ ions. Binary Ag2S NCs with different sizes were synthesized first, which then acted as the seeds to prepare different-sized AIS NCs through the incorporation of In3+. The formation mechanism of AIS NCs was studied in terms of the temporal evolution of the morphology and crystal structure, and the heterostructured Ag2S-AIS NCs were formed as intermediates during the growth process of AIS NCs. Variation in the Ag/In feeding ratios from 1 : 1 to 1 : 3 led to a broad tuning of the optical band gap and photoluminescence (PL) maximum of AIS NCs, in which very small-sized AIS NCs with a tetragonal phase were obtained. Subsequently, the incorporation of Zn2+ into AIS NCs resulted in the widening of the optical band gap and the shift of the PL maximum to higher energy with the enhancement of the absolute PL quantum yields (PLQYs). When the reaction temperature was increased, the PL emission maximum could be tuned from 2.04 to 2.33 eV and the absolute PLQYs could be tuned from 16% to 58%. Time-resolved PL spectroscopy was used to study the PL decay dynamics of the AIS and AIZS NCs, and the PL emission was related to the recombination of the surface-related states, intrinsic defects and donor–acceptor (D–A) pairs. The ternary and quaternary Ag-based semiconductor NCs have long-lived excitons, which may have promising applications in the field of energy conversion. [ABSTRACT FROM AUTHOR]

Self-powered UV photodetectors (PDs) functioning without any power supply are urgently needed in modern optoelectronic devices from the viewpoint of being energy saving, portable and miniature. In this work, we report a novel heterojunction structure on a large scale based on n-type TiO2 nanowells and p-type NiO mesoporous nanosheets in an economic route. The novel synthesis strategy using thin-layers of TiO2 nanowells instead of conventional anodic nanotube geometry enables faster charge carrier transport through a shorter diffusion pathway along the lateral direction; and the flower-like morphology of NiO nanosheets guarantees the interfacial active reaction sites to UV light exposure, which takes great advantages of the p–n junction area to enhance the generation of electron–hole pairs. The hybrid PD performed in a self-powered mode is carefully explored which shows an enhanced photoresponse including good responsivity, excellent wavelength selectivity and high stability. This work presented here opens up new avenues for developing high-performance energy-efficient devices economically with a large area. [ABSTRACT FROM AUTHOR]

With Ar plasma treatment of the indium tin oxide (ITO) cathode, we achieve efficient inverted bulk heterojunction solar cells based on poly(3-hexylthiophene):[6,6]-phenyl C61 butyric acid methyl ester, which do not require electron selective layer. The plasma treatment improves the power conversion efficiency of the device from 1.07% to 3.57% with a fill factor of 66%, open-circuit voltage of 0.60 V, and short-circuit current of 9.03 mA cm−2. This result is comparable to the regular inverted devices with an additional electron selective layer. The Kelvin probe detects a reduction in the ITO work function of ∼0.45 eV after plasma treatment, which finally leads to an increase in the built-in potential and faster carrier extraction. As a result, good device performance is achieved. Because the electron selective layer becomes unnecessary, our strategy suggests a simple way to achieve efficient inverted organic solar cells. [ABSTRACT FROM AUTHOR]