We describe the fabrication of roll-to-roll (R2R) printed organic photovoltaic (OPV) modules using gravure printing and rotary screen-printing processes. These two-dimensional printing techniques are differentiating factors from coated OPVs enabling the direct patterning of arbitrarily shaped and sized features into visual shapes and, increasing the freedom to connect the cells in modules. The inverted OPV structures comprise five layers that are either printed or patterned in an R2R printing process. We examined the rheological properties of the inks used and their relationship with the printability, the compatibility between the processed inks, and the morphology of the R2R-printed layers. We also evaluate the dimensional accuracy of the printed pattern, which is an important consideration in designing arbitrarily-shaped OPV structures. The photoactive layer and top electrode exhibited excellent cross-dimensional accuracy corresponding to the designed width. The transparent electron transport layer extended 300 µm beyond the designed values, whereas the hole transport layer shrank 100 µm. We also examined the repeatability of the R2R fabrication process when the active area of the module varied from 32.2 cm(2) to 96.5 cm(2). A thorough layer-by-layer optimization of the R2R printing processes resulted in realization of R2R-printed 96.5 cm(2) sized modules with a maximum power conversion efficiency of 2.1% (mean 1.8%) processed with high functionality.

Visible light communication systems can be used in a wide variety of applications, from driving to home automation. The use of wearables can increase the potential applications in indoor systems to send and receive specific and customized information. We have designed and developed a fully organic and flexible Visible Light Communication system using a flexible OLED, a flexible P3HT:PCBM-based organic photodiode (OPD) and flexible PCBs for the emitter and receiver conditioning circuits. We have fabricated and characterized the I-V curve, modulation response and impedance of the flexible OPD. As emitter we have used a commercial flexible organic luminaire with dimensions 99 × 99 × 0.88 mm, and we have characterized its modulation response. All the devices show frequency responses that allow operation over 40 kHz, thus enabling the transmission of high quality audio. Finally, we integrated the emitter and receiver components and its electronic drivers, to build an all-organic flexible VLC system capable of transmitting an audio file in real-time, as a proof of concept of the indoor capabilities of such a system.

Gravure printing as direct patterning roll-to-roll (R2R) production technology can revolutionize the design of thin-film organic photovoltaic (OPV) devices by allowing feasible manufacturing of arbitrary-shaped modules. This makes a distinction to coating methods, such as slot die coating, in which the pattern is limited to continuous stripes. Here, we analyze the thin-film formation and its influence on OPV module performance as the gravure printing of hole transport and photoactive layers are transferred from laboratory to R2R pilot production environment. Insertion of a 0.8-nm layer of lithium fluoride (LiF) as an interfacial layer between the active layer and the electron contact provided insulation against the detrimental pinholes formed in the R2R printing process. Using this device configuration, we produced well-performing R2Rprinted monolithic modules with a mean efficiency of 1.7%. In comparison, reference modules with an efficiency of 2.2% were fabricated using laboratory-scale bench top sheet-level process. Surface energy and tension measurements together with optical microscopy were used to analyze the printability of the materials. The pinhole insulation was investigated in detail by processing R2R-printed OPV modules with different interfacial layer materials and performing electrical measurements under dark and AM1.5 illumination conditions. Furthermore, we analyzed the LiF distribution using X-ray photoelectron spectroscopy. The insulating nature of the LiF layer to improve module performance was confirmed by manufacturing lithographically artificial pinholes in device structures. The results show the possibility to loosen the production environment constraints and the feasibility of fabricating well-performing thin-film devices by R2R gravure printing.

We present a gravure printing process for zinc oxide (ZnO) nanoparticle ink to be used as a hole‐blocking layer in inverted organic solar cells, enabling the production of patterned devices with freedom of design. The printability of the ink is optimized in a pilot‐scale roll‐to‐roll (R2R) process, leading to smooth layers having a thickness of few tens of nanometers. The properties of the printed ZnO film are further optimized using R2R post‐printing plasma treatment, which leads to increased adhesion and power conversion efficiency (PCE). The functionality of the printed ZnO layer is demonstrated in fully R2R‐printed inverted solar cells showing high performance (2.9 % mean PCE).

Organic light emitting diodes (OLED) are developing rapidly and provide a huge market potential for signage, lighting and display applications. Cost efficient manufacturing of OLED components on different flexible substrates is under heavy investigation. In this paper focus is on polymer OLEDs and their non‐vacuum solution processing using roll‐to‐roll (R2R) printing techniques. In this paper VTT's R2R manufacturing process capabilities for printed OLED components are presented. Several demonstrator concepts based on printed OLED technology are introduced including; printed OLED elements 1) in a smart package, 2) a 7‐segment display integrated in a ID‐1 card, 3) an electronics voting card with OLED indicator and 4) a 35 cm2 OLED lighting element printed on glass.