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Abstract Exploring new near-room-temperature thermoelectric materials is significant for replacing current high-cost Bi2Te3. This study highlights the potential of Ag2Se for wearable thermoelectric electronics, addressing the trade-off between performance and flexibility. A record-high ZT of 1.27 at 363 K is achieved in Ag2Se-based thin films with 3.2 at.% Te doping on Se sites, realized by a new concept of doping-induced orientation engineering. We reveal that Te-doping enhances film uniformity and (00l)-orientation and in turn carrier mobility by reducing the (00l) formation energy, confirmed by solid computational and experimental evidence. The doping simultaneously widens the bandgap, resulting in improved Seebeck coefficients and high power factors, and introduces TeSe point defects to effectively reduce the lattice thermal conductivity. A protective organic-polymer-based composite layer enhances film flexibility, and a rationally designed flexible thermoelectric device achieves an output power density of 1.5 mW cm−2 for wearable power generation under a 20 K temperature difference.

Abstract Cadmium sulfide (CdS) buffer layer is commonly used in Kesterite Cu2ZnSn(S,Se)4 (CZTSSe) thin film solar cells. However, the toxicity of Cadmium (Cd) and perilous waste, which is generated during the deposition process (chemical bath deposition), and the narrow bandgap (≈2.4 eV) of CdS restrict its large‐scale future application. Herein, the atomic layer deposition (ALD) method is proposed to deposit zinc–tin‐oxide (ZTO) as a buffer layer in Ag‐doped CZTSSe solar cells. It is found that the ZTO buffer layer improves the band alignment at the Ag‐CZTSSe/ZTO heterojunction interface. The smaller contact potential difference of the ZTO facilitates the extraction of charge carriers and promotes carrier transport. The better p–n junction quality helps to improve the open‐circuit voltage (VOC) and fill factor (FF). Meanwhile, the wider bandgap of ZTO assists to transfer more photons to the CZTSSe absorber, and more photocarriers are generated thus improving short‐circuit current density (Jsc). Ultimately, Ag‐CZTSSe/ZTO device with 10 nm thick ZTO layer and 5:1 (Zn:Sn) ratio, Sn/(Sn + Zn): 0.28 deliver a superior power conversion efficiency (PCE) of 11.8%. As far as it is known that 11.8% is the highest efficiency among Cd‐free kesterite thin film solar cells.

Abstract Antimony selenide (Sb2Se3) is an ideal photovoltaic candidate profiting from its advantageous material characteristics and superior optoelectronic properties, and has gained considerable development in recent years. However, the further device efficiency breakthrough is largely plagued by severe open‐circuit voltage (VOC) deficit under the existence of multiple defect states and detrimental recombination loss. In this work, an effective absorber layer growth engineering involved with vapor transport deposition and post‐selenization is developed to grow Sb2Se3 thin films. High‐quality Sb2Se3 with large compact crystal grains, benign [hk1] growth orientation, stoichiometric chemical composition, and suitable direct bandgap are successfully fulfilled under an optimized post‐selenization scenario. Planar Sb2Se3 thin‐film solar cells with substrate configuration of Mo/Sb2Se3/CdS/ITO/Ag are constructed. By contrast, such engineering effort can remarkably mitigate the device VOC deficit, owing to the healed detrimental defects, the suppressed interface and space‐charge region recombination, the prolonged carrier lifetime, and the enhanced charge transport. Accordingly, a minimum VOC deficit of 0.647 V contributes to a record VOC of 0.513 V, a champion device with highly interesting efficiency of 7.40% is also comparable to those state‐of‐the‐art Sb2Se3 solar cells, paving a bright avenue to broaden its scope of photovoltaic applications.

Abstract Novel glasses in a Ga2S3-Sb2S3-AgI system were prepared with a melt-quenching method, and their glass-forming region was identified. The maximum dissolvable AgI in glasses was 65 mol%. The thermal, optical, and structural properties of glasses were investigated as a function of AgI and Ga2S3 contents. The Ga2S3-Sb2S3-AgI glasses possess a wide region of transmission window (0.65−14 μm). An ionic conductivity of approximately 1.01 × 10−3 S/cm can be obtained for a 40 (0.8Sb2S3-0.2Ga2S3)-60AgI glass at an ambient temperature, and the ionic conductivity increased as temperature increased. The relative activation energy of Ag+ conduction was also calculated. These novel glasses show potential for the combined application of infrared optics and solid electrolytes.

Abstract The structural evolution and phase-change kinetics of NiO-doped ZnSb films are investigated. NiO-doped ZnSb films exhibit a single-step crystallization process, which is different from that of undoped ZnSb. NiO-doped ZnSb can directly crystallize into a stable ZnSb phase at temperatures greater than 320 °C with suppression of a metastable ZnSb phase. These characteristics enlarge the amorphous/crystalline resistance ratio by approximately five orders of magnitude. Moreover, NiO doping of ZnSb films increases crystallization temperature from 260 to 275 °C, improves data retention temperature from 201.7 to 217.3 °C and increases crystalline activation energy from 5.64 to 6.34 eV. The improvement of the thermal parameters in the nanocomposite can be attributed to stable ZnSb grain growth refinement owing to the dispersion of NiO particles in the sample matrix. This provides additional nucleation sites and produces more ZnSb/NiO interfaces, which can initiate the nucleation and accelerate crystallization. The kinetic exponent n decreases from 1.12 to 0.44, which confirms the ultrafast one-dimensional growth and heterogeneous phase transition of the NiO-doped ZnSb films. The improved thermal stability, larger resistance ratio and direct transition to a stable phase with ultrafast one-dimensional crystal growth indicate the good potential of these materials in phase-change memory applications.