Diphenylisobenzofuran Bound to Nanocrystalline Metal Oxides: Excimer Formation, Singlet Fission, Electron Injection, and Low Energy Sensitization
Diphenylisobenzofuran Bound to Nanocrystalline Metal Oxides: Excimer Formation, Singlet Fission, Electron Injection, and Low Energy Sensitization
复制标题
DOI：
10.1021/acs.jpcc.8b08599
复制
发表时间：
2018-12-20
影响因子：
3.7
通讯作者：
Hanson, Kenneth
中科院分区：
文献类型：
--
作者：
Banerjee, Tanmay;Hill, Sean P.;Hanson, Kenneth
我们报道了二羧基二苯基异苯并呋喃染料(1)与纳米晶金属氧化物表面结合的光物理性质。当表面负载增加到1时，薄膜的发射明显淬灭，但在最大表面负载下有少量的准分子发射。用ns TA光谱观察到长寿命的三重态，与中孔ZrO2上发生的单线态裂变相一致。然而，我们的亚纳秒TA光谱无法令人信服地解决这些三重体的演化。在TiO2|Al2O3核壳结构上由1组成的染料敏化器件，其J（sc）随Al2O3的厚度呈现出不同寻常的先减小后增大再减小的变化。在这些薄膜中，Al2O3作为隧道势垒，减缓了单线态激发态的电子注入，从而导致单线态裂变，而来自三重态的电子注入则成为竞争态。原理验证的自组装双层膜表现出从低能吸收染料到1的有效三重态能量转移，这是向基于sf的DSSC迈出的又一步，可以绕过Shockley-Queisser极限。
We report the photophysical properties of the dicarboxylated diphenylisobenzofuran dye (1) bound to nanocrystalline metal oxide surfaces. With increased surface loading of 1, emission from the films is significantly quenched but with a small amount of excimer emission at maximum surface loadings. Long-lived triplets were observed by ns TA spectroscopy that are consistent with singlet fission occurring on mesoporous ZrO2. The evolution of these triplets, however, could not be convincingly resolved by our subnanosecond TA spectroscopy. Dye-sensitized devices composed of 1 on a TiO2|Al2O3 core-shell structure exhibited an unusual decrease, increase, and then decrease in J(sc) with respect to the thickness of Al2O3. In these films the Al2O3 acts as a tunneling barrier to slow electron injection from the singlet excited state such that singlet fission, and electron injection from the triplet state becomes competitive. Proof-of-principle self-assembled bilayer films that exhibit efficient triplet energy transfer from a low energy absorbing dye to 1 is demonstrated as another step toward a SF-based DSSC that can circumvent the Shockley-Queisser limit.