Justifying benzoselenadiazole acceptor core as organic semiconductor for stable bulk-heterojunction organic solar cells at ambient temperature

This work describes the utilization of D-A-D type organic semiconductor,4,4’-(benzo[c][1,2,5]selenadiazole-4,7-diyl)bis(N,N-diphenylaniline),denoted as Se-2TPA,containing benzoselenadiazole(BSe)as acceptor core and end-capped with triphenylamine(TPA)donor units as donor materials in solar cells.Superlatively,the attachment of TPA donor moiety in BSe acceptor unit enlarged the conjugated system by extending the p-bonding which effectively tuned the optical and electrochemical properties of Se-2TPA.The bulk heterojunction organic solar cell(BHJ-OSCs)with configuration of ITO/cp-TiO_(2)/Se-2TPA:PC61BM/Au showed power conversion efficiency(PCE)of~4.12% with short circuit current(Jsc)value of~11.28 mA/cm^(2),open circuit voltage(Voc)of~0.775 V and fill factor(FF)of~0.48.PCE significantly increased from~4.12% to~5.29% when 1,8-diiodooctane(DIO)was added as an additive in Se-2TPA:PC61BM blend which associated with less phase separation and improved the charge extraction.The fabricated BHJ-OSCs processed with 3%DIO,ITO/cp-TiO_(2)/Se-2TPA:PC61BM/Au configuration displayed a long-term stability under air condition at an ambient temperature by maintaining~80% PCE for the duration of 30 days.The advantages of easy synthesis,low cost and promising cell performance supported Se-2TPA as successful organic semiconductor for BHJ-OSCs.

A Selenium Atom Involved Covalent Organic Framework for Window Ledge Photocatalytic Oxidation of Sulfides

Covalent organic frameworks(coFs)driven photocatalytic organic transformations especially photooxidation reactions have become a fertile topic and attracted numerous research attentions.Boosting the charge generation and transport process is the key factor for achieving high catalytic efficiencies.As one of the most effective strategies,the introduction of"heavy atoms"into the long-range ordered conjugated backbones can effectively facilitate the intersystem crossing(isc)process and hence improve the generation of active oxygens,which is beneficial for the oxidation.In this work,we designed and synthesized a benzoselenadiazole based covalent organic framework(COF)material,BSe-COF with heavy atom of selenium(Se),and a benzothiadiazole based BT-COF with isomorphic backbone for comparison.

Analyzing excited-state processes and optical signatures of a ratiomeric fluorine anion sensor: a quantum look

Recently, the spectroscopic signatures of a benzoselenadiazole derivative have been investigated in the framework of designing a new ratiometric fluoride sensor （Saravanan et al., Org Lett, 2014, 16： 354-357）. It was suggested that this sensor is un- dergoing excited-state intramolecular proton transfer. In this work, we provide a new look at these experimental data, using a state-of-the-art time-dependent density fimctiona/theory approach to mimic the spectroscopic signatures. New insights about the nature of the excited-state processes are obtained.