Future lightweight, flexible, and wearable electronics will employ visible‐light‐communication schemes to interact within indoor environments. Organic photodiodes are particularly well suited for such technologies as they enable chemically tailored optoelectronic performance and fabrication by printing techniques on thin and flexible substrates. However, previous methods have failed to address versatile functionality regarding wavelength selectivity without increasing fabrication complexity. This work introduces a general solution for printing wavelength‐selective bulk‐heterojunction photodetectors through engineering of the ink formulation. Nonfullerene acceptors are incorporated in a transparent polymer donor matrix to narrow and tune the response in the visible range without optical filters or light‐management techniques. This approach effectively decouples the optical response from the viscoelastic ink properties, simplifying process development. A thorough morphological and spectroscopic investigation finds excellent charge‐carrier dynamics enabling state‐of‐the‐art responsivities >102 mA W−1 and cutoff frequencies >1.5 MHz. Finally, the color selectivity and high performance are demonstrated in a filterless visible‐light‐communication system capable of demultiplexing intermixed optical signals.

Organic photodiodes (OPDs) are set to enhance traditional optical detection technologies and open new fields of applications, through the addition of functionalities such as wavelength tunability, mechanical flexibility, light-weight or transparency. This, in combination with printing and coating technology will contribute to the development of cost-effective production methods for optical detection systems. In this review, we compile the current progress in the development of OPDs fabricated with the help of industrial relevant coating and printing techniques. We review their working principle and their figures-of-merit (FOM) highlighting the top device performances through a comparison of material systems and processing approaches. We place particular emphasis in discussing methodologies, processing steps and architectural design that lead to improved FOM. Finally, we survey the current applications of OPDs in which printing technology have enabled technological developments while discussing future trends and needs for improvement.

Inkjet printing [13][14][15][16][17] and spray coating processes like Aerosol Jet printing (AJ), [18][19][20][21] enables an exceptional customizability as well as a cost-effective fabrication of devices perfectly matching the individual application requirements.The viability of these processes for the fabrication of entirely printed OPDs has been demonstrated in our work [18] and by others. [22] However, most of the reports so far are limited to single devices. Very recently several groups have started working on the development of processes for the fabrication of multidevice systems paving the way toward the fabrication of fully printed image sensors, micro power modules or displays. [23][24][25][26] However, the device integration and packing density in combination with consistent device performance needed for such systems has remained challenging due to limited registration accuracy, variation in the printing process stability and highly sensitive drying effects. [27,28] Commonly, these challenges are approached from either a mechanical engineering side by improving substrate or print head translations accuracy, printing form and, more recently, by substrate patterning [29,30] or through specific ink formulations that account for substrate's surface energy, viscoelastic properties, or drying-induced instabilities of the layer.In this work, we successfully overcome these challenges by exploiting a recently developed self-alignment process induced to fabricate a fully digitally printed image sensor based on organic photoactive materials with high performance, reproducibility, and lab-scale fabrication yields of 100%. The passive matrix image detector is composed of 256 micropixels with individual active areas of ≈250 µm × 300 µm for a total footprint of 64 mm 2 . To the best of our knowledge, this is the highest packing density and number of functional pixel among the reported systems not making use of evaporation techniques or a TFT-backplane. Characterization of the single OPD pixels demonstrated state-of-the art performances with spectral responsivities (SR) of up to 0.3 A W −1 , a linear dynamic range (LDR) of 114 dB and calculated specific detectivities (D*) > 10 12 Jones, thereby competing with performances of current inorganic photodetector devices. Figure 1a illustrates the OPD fabrication process. The bottom electrodes where deposited via a self-aligning process where AJ printed SU-8 lines (step I) served as dewetting structures for the inkjet printed Ag ink (step II). The dewetting process of the functional ink on SU-8 is driven by the low Here, an entirely printed passive matrix image detector composed of 256 individual pixels with an individual active area of ≈250 µm × 300 µm is fabricated. The fabrication of the organic photodetector (OPD) array is enabled by exploiting a self-alignment process of the functional layers induced by digitally printed dewetting patterns resulting in high-performance reproducibility and fabrication yields of 100%. The single OPD pixels fabricated under ambient condition...

Digitally printed organic photodiodes (OPDs) are of great interest for the cost-efficient additive manufacturing of single and multidevice detection systems with full freedom of design. Recently reported high-performance nonfullerene acceptors (NFAs) can address the crucial demands of future applications in terms of high operational speed, tunable spectral response, and device stability. Here, we present the first demonstration of inkjet and aerosol-jet printed OPDs based on the high-performance NFA, IDTBR, in combination with poly(3-hexylthiophene), exhibiting a spectral response up to the near-infrared (NIR) region. These digitally printed devices reach record responsivities up to 300 mA/W in the visible and NIR spectrum, competing with current commercially available technologies based on Si. Furthermore, their fast dynamic response with cutoff frequencies surpassing 2 MHz outperforms most of the state-of-the-art OPDs. The successful process translation from spin-coating to printing is highlighted by the marginal loss in performance compared to the reference devices, which reach responsivities of 400 mA/W and detection speeds of more than 4 MHz. The achieved high device performance and the industrial relevance of the developed fabrication process provide NFAs with an enormous potential for the development of printed photodetection systems.

The fabrication of electronics on the basis of biofriendly materials aims to counterbalance the negative trends conveyed by the short life-cycle of electronics. Furthermore, these materials open the possibility to...