Double layer distribution exists in Cu2SnZnSe4 (CZTSe) thin films prepared by selenizing the metallic precursors, which will degrade the back contact of Mo substrate to absorber layer and thus suppressing the performance of solar cell. In this work, the double‐layer distribution of CZTSe film is eliminated entirely and the formation of MoSe2 interfacial layer is inhibited successfully. CZTSe film is prepared by selenizing the precursor deposited by electrodeposition method under Se and SnSex mixed atmosphere. It is found that the insufficient reaction between ZnSe and Cu‐Sn‐Se phases in the bottom of the film is the reason why the double layer distribution of CZTSe film is formed. By increasing Sn content in the metallic precursor, thus making up the loss of Sn because of the decomposition of CZTSe and facilitate the diffusion of liquid Cu2Se, the double layer distribution is eliminated entirely. The crystallization of the formed thin film is dense and the grains go through the entire film without voids. And there is no obvious MoSe2 layer formed between CZTSe and Mo. As a consequence, the series resistance of the solar cell reduces significantly to 0.14 Ω cm2 and a CZTSe solar cell with efficiency of 7.2% is fabricated.

Raman spectroscopy (RS) is widely used as a non-invasive technique in screening for the diagnosis of oral cancer. The potential of this optical technique for several biomedical applications has been proved. This work studies the efficacy of RS in detecting oral cancer using sub-site-wise differentiation. A total of 80 samples (44 tumor and 36 normal) were cryopreserved from three different sub-sites: The tongue, the buccal mucosa, and the gingiva of the oral mucosa during surgery. Linear discriminant analysis (LDA) and quadratic discriminant analysis (QDA) were used with principal component analysis (PCA) to classify the samples and the classifications were validated by leave-one-out-cross-validation (LOOCV) and k-fold cross-validation methods. The normal and tumor tissues were differentiated under the PCA-LDA model with an accuracy of 81.25% (sensitivity: 77.27%, specificity: 86.11%). The PCA-QDA classifier model differentiated these tissues with an accuracy of 87.5% (sensitivity: 90.90%, specificity: 83.33%). The PCA-QDA classifier model outperformed the PCA-LDA-based classifier. The model studies revealed that protein, amino acid, and beta-carotene variations are the main biomolecular difference markers for detecting oral cancer.

The fabrication of kesterite CZTSe solar cells via an electrodeposition method provides an attractive approach for the low‐cost and environment‐friendly energy supply, yet the highest conversion efficiency for such solar cells (around 9%) is still far away from the highest efficiency of Cu‐based kesterite solar cells. Herein, a 10.54% efficient CZTSe solar cell (0.28 cm2 active sized area, without an antireflection layer) is developed by introducing electrodeposited Cu–Ge alloy layer at the bottom of metal precursor. It is found that the presence of Ge element within the bottom of the film can promote downward diffusion of Sn element. Consequently, the distribution of Sn is relatively homogeneous during the annealing process; thus, the formation of undesirable defect clusters is inhibited and the band alignment of the CdS/CZTSe interface is optimized. As a result, the conversion efficiency of CZTSe thin‐film solar cells is increased from 6.74% to 10.54%, which is the highest efficiency reported for electrochemically fabricated CZTSe solar cells.

In this work, high open circuit voltages (Voc) of In0.2Ga0.8N and In0.28Ga0.72N multiple quantum well solar cells (MQWSCs) are experimentally obtained (2.2 V and 1.8 V, respectively). The Voc of In0.28Ga0.72N MQWSCs is lower than the expected value due to serious indium segregation problems causing more defects in In0.28Ga0.72N films, which is consistent with the observation of a high ideality factor in dark current measurement. The temperature dependence of the Voc and the short circuit current (Jsc) in In0.2Ga0.8N MQWSCs is found to be larger than the corresponding values in In0.28Ga0.72N MQWSCs. It is also observed that higher quantum well energy barrier exhibits a low fill factor of 0.52 due possibly to the loss of electric field and the higher energy barrier. This obtained efficiency increases with temperatures up to 100 °C and then decreases due to competing results between the reduction in Voc and an increase in Jsc.

This work studies the use of gold (Au) and silver (Ag) nanoparticles in multicrystalline silicon (mc-Si) and copper-indium-gallium-diselenide (CIGS) solar cells. Au and Ag nanoparticles are deposited by spin-coating method, which is a simple and low cost process. The random distribution of nanoparticles by spin coating broadens the resonance wavelength of the transmittance. This broadening favors solar cell applications. Metal shadowing competes with light scattering in a manner that varies with nanoparticle concentration. Experimental results reveal that the mc-Si solar cells that incorporate Au nanoparticles outperform those with Ag nanoparticles. The incorporation of suitable concentration of Au and Ag nanoparticles into mc-Si solar cells increases their efficiency enhancement by 5.6% and 4.8%, respectively. Incorporating Au and Ag nanoparticles into CIGS solar cells improve their efficiency enhancement by 1.2% and 1.4%, respectively. The enhancement of the photocurrent in mc-Si solar cells is lower than that in CIGS solar cells, owing to their different light scattering behaviors and material absorption coefficients.

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Large particle sizes having a strong light scattering lead to a significantly decreased surface area and small particle sizes having large surface area lack light-scattering effect. How to combine large and small particle sizes together is an interesting work for achieving higher solar efficiency. In this work, we investigate the solar performance influence of the dye-sensitized solar cells (DSSCs) by the multiple titanium oxide (TiO2) layers with different particle sizes. It was found that the optimal TiO2thickness depends on the particle sizes of TiO2layers for achieving the maximum efficiency. The solar efficiency of DSSCs prepared by triple TiO2layers with different particle sizes is higher than that by double TiO2layers for the same TiO2thickness. The choice of particle size in the bottom layer is more important than that in the top layer for achieving higher solar efficiency. The choice of the particle sizes in the middle layer depends on the particle sizes in the bottom and top layers. The mixing of the particle sizes in the middle layer is a good choice for achieving higher solar efficiency.

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