Light gain amplification in microcavity organic semiconductor laser diodes under electrical pumping

Organic semiconductor is one of the most promising luminescent and lasing materials that can be chemically synthesized with a controllable performance and possess high cross-section of stimulated emission . Organic semiconductor laser diodes （OSLDs） can be prepared by simple processing technologies and integrated easily with other optoelectronic devices. As a result, OSLDs would have appealing applications in low cost, compact, flexible and tunable lasers with spectral region from ultraviolet to near infrared . Although lasing has been widely demonstrated under optical pumping, electrically pumped OSLDs are rather difficult to realize because the expected high threshold current is hard to reach in low electrical conductivity organic semiconductors and electroluminescence （EL） efficiency is much decreased under high current.