Green-Sensitive Organic Photodetectors with High Sensitivity and Spectral Selectivity Using Subphthalocyanine Derivatives

Abstract

Green-sensitive organic photodetectors (OPDs) with high sensitivity and spectral selectivity using boron subphthalocyanine chloride (SubPc) derivatives are reported. The OPDs composed of SubPc and dicyanovinyl terthiophene derivative (DCV3T) demonstrated the highest green-sensitivity with maximum external quantum efficiency (EQE) of 62.6 % at an applied voltage of -5 V, but wide full-width-at-half-maximum (FWHM) of 211 nm. The optimized performance considering spectral selectivity was achieved from the composition of N,N-dimethyl quinacridone (DMQA) and SubPc showing the high specific detectivity (D*) of 2.34 × 10(12) cm Hz(1/2)/W, the EQE value of 60.1% at -5 V, and narrow FWHM of 131 nm. In spite of the sharp absorption property of SubPc with the maximum wavelength (λmax) at 586 nm, the EQE spectrum showed favorable green-sensitivity characterized by smooth waveform with λmax at 560 nm, which is induced from the high reflectance of SubPc centered at 605 nm. The photoresponsivity of the OPD devices was found to be consistent with their absorptance. Optimized DMQA/SubPc device showed the lowest value of blue crosstalk (0.42) and moderate red crosstalk (0.37), suggesting its promising application as a green-sensitive OPD.

Efficiency and spectral performance of narrowband organic and perovskite photodetectors: a cross-sectional review

“…The reasons for this are manifold: (a) the ease and attractiveness of the NBA approach to achieve narrowband photodetection (section 5.1); (b) the later development of CCN and microcavity approaches; (c) the limited edge of the input-filtered strategy (in view of its overlap with conventional narrowband photodetection, with which it shares similar challenges). In primary photocurrent mode, the NBA strategy has led to the highest EQE figures of all narrowband approaches (up to 60%-80%), as exemplified by figure 6(a) [46,57,58,61,70,95,128,129]. This can be rationalised in terms of its straightforward operation, which does not require filtering and/or the introduction of deliberate loss mechanisms.…”

“…Small-molecule semiconductors with narrowband absorption properties have played a key role in the development of organic narrowband photodetectors (see section 5.1). A significant number of them are drawn or derived from compounds originally developed as industrial colourants, laser dyes, or fluorescent probese.g., blue-absorbing coumarins [22,[44][45][46][47], green-absorbing rhodamines [44,45,[48][49][50][51] and quinacridones [11,47,[52][53][54][55][56][57][58][59][60][61][62][63], green-and red-absorbing phthalocyanine metal/metalloid complexes and derivatives [11, 44, 45, 47, 49, 54-56, 58, 61, 64-70], and green-, red-, and NIR-absorbing squaraines [23,[71][72][73] ( figure 4(b)). It is noteworthy that some narrowband-absorbing small molecules are able to form aggregates (Jand H-aggregates) featuring particularly narrow and intense absorption bands (FWHM α <20 nm, α up to 10 6 cm −1 ), a property that is very attractive for narrowband photodetection [24,[74][75][76][77][78][79].…”

“…Their outstanding electron-accepting properties in BHJs and PHJs (in combination with polymeric and smallmolecule donors alike) have led to their widespread use in all types of narrowband photodetector configurations [19,30,31,[80][81][82][83][84][85]. However, their broad absorption tail through the visible has been problematic in some configurations (see section 6.3), and this has recently prompted the development of alternative small-molecule acceptors with narrowband absorption [11,[57][58][59][60][61] or with diverse onsets [42,[86][87][88].…”

“…Organic green-selective photodetectors have achieved the highest quantum efficiency (>50%) in primaryphotocurrent mode through the NBA approach [11, 57-59, 61, 120, 128, 129, 133]. A large number of these works rely on green-absorbing quinacridone dye derivatives (used as donors) [11,[57][58][59]61], leading to a maximum EQE p of 67.6% in combination with green-absorbing DCV3T (used as an acceptor) ( figure 7(b)) [57]. Chloroboron subphthalocyanine (SubPc) is another small molecule that has delivered high phototransduction efficiency in a number of works, giving an EQE p of 62.6% in combination with DCV3T [58], and 60.1% in combination with quinacridone [58,61] (figure 7(b)).…”

“…A large number of these works rely on green-absorbing quinacridone dye derivatives (used as donors) [11,[57][58][59]61], leading to a maximum EQE p of 67.6% in combination with green-absorbing DCV3T (used as an acceptor) ( figure 7(b)) [57]. Chloroboron subphthalocyanine (SubPc) is another small molecule that has delivered high phototransduction efficiency in a number of works, giving an EQE p of 62.6% in combination with DCV3T [58], and 60.1% in combination with quinacridone [58,61] (figure 7(b)). Newly synthesised small-molecule donors featuring a D-A structure approaching the cyanine limit have also yielded EQE values in the ≈50%-70% range in combination with fullerenes ( figure 7(b)) [120,126,128,129].…”