Non-contact and non-destructive in-situ inspection for CdSe quantum dot film based on the principle of field-induced photoluminescence quenching

CdSe quantum-dot (QD) film, as the core function layer, plays a key role in various optoelectronic devices. The thickness uniformity of QD films is one of the key factors to determine the overall photoelectric performance. Therefore, it is important to obtain the thickness distribution of large-area QD films. However, it is difficult for traditional methods to quickly get the information related to its thickness distribution without introducing additional damage. In this paper, a non-contact and non-destructive inspection method for in-situ detecting the thickness uniformity of CdSe QD film is proposed. The principle behind this in-situ inspection method is that the photoluminescence quenching phenomenon of the QD film would occur under a high electric field, and the degree of photoluminescence quenching is related to the thickness of the quantum dot films. Photoluminescence images of the same QD film without and with an electric field are recorded by a charge-coupled device camera, respectively. By transforming the brightness distribution of these two images, we can intuitively see the thickness information of the thin film array of QD. The proposed method provides a meaningful inspection for the manufacture of QD based light-emitting display.