gaining popularity among researchers due to the versatility of these devices for their

sensitivity to NIR light. Single junction and tandem OPV cells based on a bulky hetero­

junction were considered, and these cells’ voltage and charge storing time were in­

vestigated [17]. The efficiency of the tandem cells was reportedly higher than the

single junction PV cells (5.6% in comparison to 5.3%). The added advantage of tunability

of the tandem OPV cells such as in retinal applications in which the light intensity is

limited in the range of 150–600 mW/cm². The tandem OPV cells with an active area of

2,500–6,250 µm² and electrode diameter of 35 µm can effectively tune the requirements in

comparison to the single junction OPV that has an effective diameter of 60 µm of the

FIGURE 20.5

(a–i) Illustration of the timeline associated with the development of the PV cells from 1990 to 2030. Adapted

with permission [ 17]. Copyright The Authors, some rights reserved; exclusive licensee John Wiley & Sons.

Distributed under a Creative Commons Attribution License 4.0 (CC BY).

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