Polycarbazole-based organic photodiodes for highly sensitive chemiluminescent immunoassays

It is reported the development of a polycarbazole-based organic photodetector for chemiluminescent immunoassays. The optical detector comprised a 1:4 blend by weight of poly [N-9´-heptadecanyl-2,7-carbazole-alt-5,5-(4´,7´-di-2-thienyl-2´,1´,3´-benzothiadiazole)] (PCDTBT) and [6,6]-phenyl C₇₁-butyric acid methyl ester (PC₇₀BM). Optimization of the photodetector design was conducted aiming to maximize photosensitivity and reduce the background level. Quantitation of recombinant human thyroid stimulating hormone indicated good linearity and yielded a detection sensitivity of ~3.7 nA × nM^-1 and a detection limit of 80 pg/ml.