SPIE Proceedings [SPIE 7th International Symposium on Advanced Optical Manufacturing and Testing Technologies (AOMATT 2014) - Harbin, China (Saturday 26 April 2014)] 7th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Optoelectronics Materials and Devices for Sensing and Imaging - The study of the effect on the organic emitting diodes with (t-bt) 2 Ir(acac) as deep hole-trap