1. Search for Electron-Deficient Semiconducting Polymers to Rival Fullerenes Luping Yu, University of Chicago, DMR 1263006 This project is aimed at developing novel electron accepting polymers for replacing the PCBM derivatives used in the active layers of organic photovoltaic devices and investigating structure/property relationships. In the past year, a significant progress was made in developing new n-type polymers (e.g. PQPDI). PQPDI was synthesized by copolymerization of a weak electron accepting monomer 5,11-bis(2-butyloctyl)-dihydrothieno [2',3':4,5]-pyrido[2,3-g]thieno[3,2-c]quinoline-4,10-dione and a strong accepting monomer perylyene diimide. The bulk heterojunction photovoltaic devices fabricated with the following configuration: ITO/PEDOT:PSS/PTB10:PQPDI/Ca/Al, showed a PCE value of 3.52 % (Voc = 0.71 V, Jsc = -8.58 mA/cm2, FF = 0.58) at a weight ratio of PTB10:PQPDI = 1:1 when gold nanorods were incorporated in the PEDOT-PSS layer. Another significant development is our discovery of a new mechanism for enhancing PCE in a ternary system. A hole relay polymer (PID2) was synthesized and shown to enhance the PCE significantly. Detailed studies indicated that the polymer played the role of both hole transport relay and nuclear centers for the assembly of PTB7 polymer chains. Efficiency as high as 9.3% was obtained recently. Figure 2. a). Structures of PTB7 and PID2; b). current-voltage characteristics of solar cells with different compositions. Nature Photonics, Accepted, 2014. Figure 1. a). Structures of PQPDI and PTB10; b). current-voltage characteristics of solar cells with different compositions. a. b.

2. Educational outreach and diversity: This is an interdisciplinary project that offers opportunity for training in organic synthesis, physical measurements, device evaluation, and theoretical calculation using density functional theory. Inspired by the success of the last year, we have succeeded in recruiting a female graduate student (Dongling Zhao) and a female postdoctoral associate (Dr. Aireal Jenkins) to our group. Most recently, we have succeeded in recruiting and supporting an underrepresented student (Mr. Cameron Menezes) to work in summer project. We also recruited a female high school student (Miss Jessica Lu ) to join this project for summer research. At the same time, our group is hosting an international REW student from Zhejiang University of China. They have started the training in fabrication of organic solar cell devices, measurement of current density-voltage (J- V) characteristics and organic synthesis. A new monomer with high fluorescent emission at near IR region was synthesized by Mr. Menezes. Numerous interesting data have been collected by Misses Zhao and Lu. They are now in the process learning how to analyze them. Outreach: The PI has succeeded in establishing more collaborations with several companies, including Solarmer Energy for solar cell devices, Zhejiang Pharmas. Solarmer just negothiated the sharing arrangement of our patents’ right with Phllipe 66 company. In the past three years, the PI enjoys close collaborations with several research groups and national and industrial labs: Prof. Tobin J. Marks at Northwest University on device fabrication and characterization; Dr. Lin Chen at Argonne National Lab (ANL) on electronic dynamics of low band gap polymers; Professor Yang Yang at UCLA on Inverted solar cells; Dr. Dean M. DeLongchamp (NIST), on OPV polymer morphologies, Professor R Izquierdo from Université du Québec à Montréal, Canada on environmental sensors using OPV detectors. All of these collaborations resulted in publications in highly respected journals. An important collaboration with Hong Kong University on organic electronic materials is undergoing. Search for Electron-Deficient Semiconducting Polymers to Rival Fullerenes Luping Yu, University of Chicago, DMR 1263006