Organic field effect transistors consisting of Poly [N- 9′-heptadecanyl-2, 7-carbazole-alt-5, 5-(4′, 7′-di-2-thienyl-2′, 1′, 3′-benzothiadiazole] (PCDTBT) as active layer have been fabricated for detection of gases. The device exhibited highly selective response towards parts- per-million level of NO₂ gas. For these devices response towards NO₂ decreases with increasing gate bias due to the existing high density of free charges. A model has been developed to explain this variation of response with gate bias using transfer characteristics of the device (in air). This model enables to determine the density of holes released in PCDTBT layer on interaction with NO₂ gas.

有机场效应晶体管，由聚[N-9'-十七碳烯基-2、7-咔唑-alt-5、5-（4'，7'-二-2-噻吩基-2'，1'，3'-苯并噻二唑组成]]]（PCDTBT）作为活性层已经被制造出来用于检测气体，该器件对百万分之几的NO ₂气体表现出高度选择性的响应，由于存在较高的栅极偏压，这些器件对NO _2的响应随栅极偏压的增加而降低。自由电荷的密度：已经开发了一个模型来解释这种通过使用器件的转移特性（在空气中）而引起的栅极偏置的响应变化，该模型可以确定PCDTBT层中与NO ₂气体相互作用释放的空穴的密度。