P–n Diodes showed a sound self-biased photovoltaic behavior upon light illumination and also achieved V _OC switching behavior at the p–n diode state by switching on and off the light.

Noble metal dichalcogenides (NMDs) are two-dimensional (2D) layered materials that exhibit outstanding thickness-dependent tunable-bandgaps that can be suitable for various optoelectronic applications. Here, we developed high-performance switching photodiodes based on mix-dimensional 2D palladium diselenide (PdSe₂) and three-dimensional (3D) silicon (Si) heterojunctions with a broadband spectral response by a mechanical exfoliation technique. We studied the gate-tunable rectifying behavior of n-PdSe₂/p-Si diodes employing an ionic liquid gate and achieved a maximum diode rectification ratio I_f/I_r up to ∼1.0 × 10⁵ with the lowest value of ideality factor ∼1.22 (at V_tg = −2 V). At different temperatures (60 to 300 K), Zener tunneling and avalanche breakdown phenomena were detected at the junction of PdSe₂–Si. These devices showed excellent self-driven photoresponses over broadband wavelengths from 400 to 1200 nm. The response speed of estimated is 9.2/17.3 μs, which represents a fast photoresponse. Moreover, in our devices, open-circuit voltage (V_OC = 0.6 V) switching behavior is attained with the on/off state of the incident light. Moreover, these devices were attested for dynamic rectification, and this effectively rectified an input alternating-voltage sine wave signal to an output signal. The results of this study indicate that 2D PdSe₂ can be employed for high-performance optoelectronic applications.

Here, novel lateral PtSe₂ p–n junctions are fabricated based on the PtSe₂/BN/graphene (Gr) van der Waals heterostructures upon the illumination of visible light via the optical excitation of the mid-gap point defects in hexagonal boron nitride (h-BN).

For the first time, density functional theory (DFT) calculations have been employed for the measurement of the structural, mechanical, optical, and electrical properties of a bismuth-layered structure ferroelectrics (BLSFs) family member possessing an orthorhombic structure with Cmc2₁ space group. Based on the exchange–correlation approximation, our calculations show that Pb₂Bi₄Ti₅O₁₈ possesses an indirect band gap, while the materials X₂Bi₄Ti₅O₁₈ (X = Ba, Ca, and Sr) demonstrate direct band gap, where the estimated density functional fundamental band gap values lie between 1.84 to 2.33 eV, which are ideal for photovoltaic applications. The optical performance of these materials has been investigated by tuning the band gaps. The materials demonstrated outstanding optical characteristics, such as high absorption coefficients and low reflection. They exhibited impressive absorption coefficient (α = 10⁵ cm⁻¹) throughout a broad energy range, especially in the visible spectrum (10⁵ cm⁻¹ region). The findings show that the compounds demonstrate lower reflectivity in the visible and UV regions, making them suitable for single-junction photovoltaic cells and optoelectronic applications. The Voigt–Reuss–Hill averaging technique has been employed to derive elastic parameters like bulk modulus (B), Young’s modulus, shear modulus (G), the Pugh ratio (B/G) and the Frantesvich ratio (G/B) at 0.1 GPa. The mechanical stability of the compounds was analyzed using the Born stability criteria. Pugh’s ratio and Frantesvich’s ratio show that all the compounds are ductile, making them ideal for flexible optical applications.

For the first time, we explored the optical, electronic, mechanical, and structural properties of the Ruddlesden–Popper phase family member X₂CaTa₂O₇ (X = Li, Na, K, and Rb) by using density functional theory (DFT) with the Perdew–Burke–Ernzerhof (PBE) function in the generalized gradient approximation (GGA) framework. These materials show promising potential for energy conversion applications. Detailed investigations into structural parameters, band gaps, total and partial densities of states, and optical and mechanical properties demonstrate their suitability for photovoltaic technologies. The calculated electronic band gap structures and density of states demonstrate that X₂CaTa₂O₇ (X = Li, Na, K, and Rb) are semiconductors in nature with band gaps ranging from 1.52 eV to 3.02 eV. Measurements demonstrate substantial contributions from O-2p⁴, Ca-4p⁴, and Ta-4f¹⁴ orbitals to the electronic structures of the compounds. Moreover, the optical characteristics, like the reflectivity, absorption coefficients (10⁵ cm⁻¹), dielectric functions (8.5), refractive index (2–3), and optical conductivity (4–6 fs⁻¹), highlight the abilities of these compounds for optoelectronic and photovoltaic devices. Additionally, the mechanical properties measurements of the compounds show that they are capable for flexible electronic applications as well. This manuscript provides good insights into the design and development of the compounds capable for next-generation photovoltaic devices.

In this article, nanocrystals were co-doped with polymer for the fabrication of microfibers by using a simple drawing process. The microstructural characteristics of tetragonal-LiYF₄:Yb³⁺/Er³⁺ nanocrystals were probed by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) techniques. The optical properties such as transmission losses and temperature dependent luminescence of a microfiber were demonstrated under 980 nm excitation. In addition, the fluorescence intensity ratio method (FIR) was utilized to carry out the optical thermometry based on green up-conversion luminescence behavior of nanocrystals in a single microfiber under two thermally coupled levels (²H_11/2→⁴I_15/2, ⁴S_3/2→⁴I_15/2) at 522 and 542 nm respectively. The high sensitivity of a microfiber was derived from the FIR technique at 358 K around 0.00307 K⁻¹ in the temperature range of 298-358 K. These results revealed that a single microfiber is promising candidate for applications in optical temperature sensor.