.jpg)
MESOSCOPIC OPTOELECTRONIC DEVICES COMPRISING ARRAYS OF SEMICONDUCTOR PILLARS DEPOSITED FROM A SUSPENSION AND PRODUCTION METHOD THEREOF
WO2012078063
The invention illustrates an innovative way to fabricate low cost, efficient, rigid or flexible mesoscopic optoelectronic devices such as photovoltaic (PV) solar cells or photo sensors (b) comprising three-dimensional arrays of semi-conductive micro- or nano-pillars (3b) deposited from suspensions e.g. by inkjet printing. Said pillars additionally increase the surface area of the device composed of an interpenetrating network of semiconductor particles of mesoscopic (2-50 nm) size forming junctions. In the present invention the active surface area is significantly increased when compared to previous flat structures (a, 3a), being fabricated preferably by inkjet patterning. Additionally, the invention allows for production of much more functional devices when compared with conventional mesoscopic PV cells due to smaller structure density what makes the layer more resistive to mechanical failure when bending. The invention also describes the device substrate (1), contact and electrode (2, 8), ion conductor (6) and fabrication parameters (h, d).
Most solar cells industrially produced are currently based on silicon wafers. As a result, the price of photovoltaic modules is very high and it is still expected to increase due to a fast growing demand and a shortage in silicon production. The cost of the most efficient (30%) tandem solar cells based oh III/IV semiconductors is very high, limiting their applications to space and solar concentrators [2]. Single-crystal silicon solar cells with power conversion efficiency of more than 25 % are heavy and fragile, which prevents them from being used for mobile applications [3]. However., there is an increasing awareness of the possible advantages of devices based on mesoscopic inorganic and organic semiconductors commonly referred to bulk junction dye to their interconnected 3D structure. Mesoscopic injection solar cells; operate in an entirely different manner from conventional solar p-n junction devices. Mimicking the principles of natural photosynthesis, they separate light harvesting from charge-carrier transport. The semiconductors that conventional cells use assume both functions simultaneously, imposing stringent demands on purity and entailing high material and production costs.