Fluorescent organic compounds are of significant importance to the development of low-cost opto-electronic devices. Blue fluorescence from aromatic or olefinic molecules and their derivatives is particularly important for display and lighting applications. Thin film deposition of low-molecular-weight fluorescent organic compounds typically requires costly vacuum evaporation systems. On the other hand, solution-processable polymeric counterparts generally luminesce at longer wavelengths due to larger delocalization in the chain. Blue light emission from solution-processed materials is therefore of unique technological significance. Here we report near-UV to blue photoluminescence (PL) from solution-processed graphene oxide (GO). The characteristics of the PL and its dependence on the reduction of GO indicates that it originates from the recombination of electron-hole (e-h) pairs localized within small sp2 carbon clusters embedded within an sp3 matrix. These results suggest that a sheet of graphene provides a parent structure on which fluorescent components can be chemically engineered without losing the macroscopic structural integrity. Our findings offer a unique route towards solution-processable opto-electronics devices with graphene.
Identification of CaCuSi$_4$O$_{10}$ (Egyptian blue) in the "Birch. Spring" painting by Robert Falk (1907) using photoluminescence
我们在"桦树"的油漆层中发现了埃及蓝色素。“春天”由罗伯特福尔克（1907年）绘画;我们也发现这种颜料在画布背面绘制的素描颜料。这可能是在20世纪的艺术作品中首次发现埃及蓝。我们分析了现代商业埃及蓝颜料（Kremer），发现它适合作为光致发光光谱分析的标准。CaCuSi $_4$ O $_{10}$的特征光致发光峰在910 nm附近达到最大值。发光被非相干绿光或蓝光有效地激发。研究表明，非相干光激发的光致发光光谱显微分析可以有效地用于艺术品漆层中发光颜料的鉴定。
Highly Efficient Blue Host-Free and Host-Guest Organic Light-Emitting Diodes Based on Carbene-Metal-Amides
基于CF $_3$ -取代的咔唑配体的卡宾-金属-酰胺型光发射体显示出从电荷转移激发态的天蓝色到深蓝色的光致发光。它们适合于通过热气相沉积技术并入有机发光二极管（OLED）中，或者嵌入在高三重态能量主体内，或者无主体使用。我们报道了具有从黄色到蓝色范围的发射的高效OLED（国际照明委员会（CIE）坐标从[0.35，0.53]到[0.17，0.17]）。后者在极性主体中显示出20.9 $\%$的峰值电致发光外量子效率（EQE）。我们观察到，CT和$^{3}$ LE态的相对能量影响卡宾金属酰胺材料的深蓝色发光性能。我们报告原型主机无蓝色器件的峰值外量子效率为17.3 $\%$，保持高性能的亮度水平为100 cd m $^{-2}$。
Pressure induced emission enhancement and bandgap narrowing: experimental investigations and first principles theoretical simulations on a model halide perovskite
Blue-Green Emission from Epitaxial Yet Cation-Disordered ZnGeN$_{2-x}$O$_x$
ZnGeN $_2$提供了InGaN的低成本替代品，具有使用阳离子位点排序进行带隙调谐以跨越绿色带隙的潜力。在阴离子位点上添加氧产生额外程度的电子可调谐性。在这里，我们研究的结构和光电性能的外延ZnGeN $_{2-x}$ O $_{x}$薄膜库的组合共溅射生长的c-Al $_2$ O $_3$。样品表现出X射线衍射图案和X射线极图特征的纤锌矿（阳离子无序）结构与预期的6倍面内对称性。透射电子显微镜揭示了一个半相干界面与周期性位错，缓解应变从大的晶格失配，并确认了面内和面外的晶体取向。室温下的光致发光表现出2.4和2.8 eV之间的峰，这是一致的尖锐的吸收开始观察到的紫外-可见光谱。这些结果证明了光学活性但阳离子无序的ZnGeN $_{2-x}$ O $_{x}$的低成本合成，表明了作为蓝绿色发光体的应用途径。
