In order to increase the efficiency of photovoltaic solar cells, photon absorption in an extended range of the solar spectrum is necessary, for example by means of up-conversion (UC) of sub-bandgap photons to minimize transparency losses. While lanthanide (Ln)-doped luminescent layers may be deposited on cell materials to achieve spectral conversion by methods like CVD or PVD, sol-gel (SG) processing is a low-cost technology which may be a good alternative for this purpose. In this work, Ln-doped SG-derived active layers have been deposited by spin-coating onto c-Si substrates for frequency conversion, with particular emphasis on UC, involving host matrices like aluminosilicate glass and titania ceramic doped with the activator/sensitizer pair Er/Yb. White light emitting diodes (WLEDs) based on Ln-doped phosphors still have efficiency limitations, namely because the Stokes shift from UV/blue LED excitation to the emitted lower frequency visible light converts some of the pump energy into heat. However, if white light generation (WLG) is achieved through IR-pumped UC instead, the cost of the LED lamp will be reduced, while the energy loss from Stokes shift can be minimized. SG synthesis of Ln-doped oxide phosphors for UC in WLG has been achieved (Er/Yb and Tm/Er/Yb doping), based on aluminosilicate glass matrices. Photonic crystal-assisted UC emission has also been demonstrated in a Tm/Yb-doped Fabry–Perot microcavity (MC). The different materials have been characterized by XRD, SEM, ellipsometry and photoluminescence (PL) spectroscopies and their light emission has been analyzed with the help of CIE chromaticity diagrams.

为了提高光伏太阳能电池的效率，必须在扩展的太阳光谱范围内吸收光子，例如借助于子带隙光子的上转换（UC），以最大程度地减少透明性损失。尽管可以通过诸如CVD或PVD的方法将掺有镧系元素（Ln）的发光层沉积在电池材料上以实现光谱转换，但是溶胶-凝胶（SG）处理是一种低成本的技术，对于该目的而言可能是一个很好的选择。在这项工作中，通过旋涂在c-Si基板上进行频率转换，特别是在UC上，将Ln掺杂的SG衍生的活性层沉积到c-Si基板上，其中涉及基质基质，例如铝硅酸盐玻璃和掺杂有活化剂/敏化剂对的二氧化钛陶瓷。 // Y 基于Ln掺杂的磷光体的白光发光二极管（WLED）仍然存在效率限制，这是因为斯托克斯从UV /蓝光LED激发转移到发出的低频可见光，从而将泵浦能量转化为热量。但是，如果改为通过红外泵浦的UC实现白光产生（WLG），则LED灯的成本将降低，而斯托克斯频移带来的能量损失则可以降至最低。基于铝硅酸盐玻璃基体，已经实现了在WLG中UC的Ln掺杂氧化物磷光体的SG合成（Er / Yb和Tm / Er / Yb掺杂）。在掺有Tm / Yb的法布里-珀罗微腔（MC）中也证明了光子晶体辅助的UC发射。通过XRD，SEM，椭圆偏振和光致发光（PL）光谱对不同材料进行了表征，并借助CIE色度图分析了它们的发光。