利用室温磷光碳点提供的超长寿命三重态激子促进石墨相氮化碳的光催化性能

Ultralong-lived triplet excitons of room-temperature phosphorescent carbon dots located on g-C_(3)N_(4) to boost photocatalysis

半导体光催化剂目前受到了广泛的关注与研究,但其光生电子和空穴的复合导致能量损失,制约着这类催化剂的应用.本工作利用具有超长寿命的三重态激子来促进电子和空穴对的有效分离,以产生更多的自由载流子.与传统的荧光碳点(CD)相比,高度分散在石墨相氮化碳上的室温磷光(RTP)碳点显示出显著提升的光催化能力和电化学活性.实验和理论计算都表明,RTP CD@g-C_(3)N_(4)可以作为“能量缓释胶囊”,不断提供长寿命的三重态激子,从而有效地调控电子和空穴对的解离,并增强催化剂固有的光催化性能(包括水分解和染料降解反应).本工作提供了一种将超长寿命三重态激子用作光催化剂的设计思路.

Semiconductor photocatalysts have recently received growing attention,but still meet the challenges of a weak separation ability of photogenerated electrons and holes,which leads to energy loss.In this work,we utilize ultralong-lived triplet excitons to promote the separation of electronhole pairs and to realize the efficient transformation from excitons to carriers.Room temperature phosphorescent(RTP)carbon dots(CDs)were selected as a model system,which were highly dispersed onto g-C_(3)N_(4)and exhibited largely enhanced photocatalytic and electrochemical activities compared with those of typical fluorescent CD systems.Both experimental and density functional theory calculations show that the ultralong-lived triplet excitons from RTP CD@g-C_(3)N_(4)serve as an“energy sustained-release capsule”and thus effectively regulate the recombination of excitons and boost the intrinsic photocatalytic performances(including water splitting and dye degradation).Therefore,this work provides a new design strategy to use ultralong-lived triplet excitons as high-efficiency photocatalysts.