Hydrophobic Hydrogen-Bonded Polymer Network for Efficient and Stable Perovskite/Si Tandem Solar Cells

The pursuit of highly efficient and stable wide-band gap (WBG) perovskite solar cells (PSCs), especially for monolithic perovskite/silicon tandem devices, is a key focus in achieving the commercialization of perovskite photovoltaics. In this study, we initially designed poly(ionic liquid)s (PILs) with varying alkyl chain lengths based on density functional theory calculations. Results pinpoint that PILs with longer alkyl chain lengths tend to exhibit more robust binding energy with the perovskite structure. Then we synthesized the PILs to craft a hydrophobic hydrogen-bonded polymer network (HHPN) that passivates the WBG perovskite/electron transport layer interface, inhibits ion migration and serves as a barrier layer against water and oxygen ingression. Accordingly, the HHPN effectively curbs nonradiative recombination losses while facilitating efficient carrier transport, resulting in substantially enhanced open-circuit voltage (Voc ) and fill factor. As a result, the optimized single-junction WBG PSC achieves an impressive efficiency of 23.18 %, with Voc as high as 1.25 V, which is the highest reported for WBG (over 1.67 eV) PSCs. These devices also demonstrate outstanding thermostability and humidity resistance. Notably, this versatile strategy can be extended to textured perovskite/silicon tandem cells, reaching a remarkable efficiency of 28.24 % while maintaining exceptional operational stability.

A-D-A Molecule-Bridge Interface for Efficient Perovskite Solar Cells and Modules

As the photovoltaic field endeavors to transition perovskite solar cells (PSCs) to industrial applications, inverted PSCs, which incorporate fullerene as electron transport layers, have emerged as a compelling choice due to their augmented stability and cost-effectiveness. However, these attributes suffer from performance issues stemming from suboptimal electrical characteristics at the perovskite/fullerene interface. To surmount these hurdles, an interface bridging strategy (IBS) is proposed to attenuate the interface energy loss and enhance the interfacial stability by designing a series of A-D-A type perylene monoimide (PMI) derivatives with multifaceted advantages. In addition to passivating defects, the IBS plays a crucial role in facilitating the binding between perovskite and fullerene, thereby enhancing interface coupling and importantly, improving the formation of fullerene films. The PMI derivatives, functioning as bridges, serve as a protective barrier to enhance the device stability. Consequently, the IBS enables a remarkable efficiency of 24.62% for lab-scale PSCs and an efficiency of 18.73% for perovskite solar modules craft on 156 × 156 mm2 substrates. The obtained efficiencies represent some of the highest recorded for fullerene-based devices, showcasing significant progress in designing interfacial molecules at the perovskite/fullerene interface and offering a promising path to enhance the commercial viability of PSCs.

Optimization of Vertical Double-Diffused Metal-Oxide Semiconductor (VDMOS) Power Transistor Structure for Use in High Frequencies and Medical Devices

Power transistors, such as the vertical, double-diffused, metal-oxide semiconductor (VDMOS), are used extensively in the amplifier circuits of medical devices. The aim of this research was to construct a VDMOS power transistor with an optimized structure to enhance the operation of medical devices. First, boron was implanted in silicon by implanting unclamped inductive switching (UIS) and a Faraday shield. The Faraday shield was implanted in order to replace the gate-field parasitic capacitor on the entry part of the device. Also, implanting the UIS was used in order to decrease the effect of parasitic bipolar junction transistor (BJT) of the VDMOS power transistor. The research tool used in this study was Silvaco software. By decreasing the transistor entry resistance in the optimized VDMOS structure, power losses and noise at the entry of the transistor were decreased, and, by increasing the breakdown voltage, the lifetime of the VDMOS transistor lifetime was increased, which resulted in increasing drain flow and decreasing Ron. This consequently resulted in enhancing the operation of high-frequency medical devices that use transistors, such as Radio Frequency (RF) and electrocardiograph machines.