Regioregular polythiophenes having heteroatoms in the substituents can be used in hole injection layer and hole transport layers for electroluminescent devices. A capillary is associated with the housing and the window. Once the reservoir and the cell sample surface are appropriately positioned, focused acoustic energy is applied to eject a droplet of the fluid from the reservoir. An elongated tube is procured and an end portion of the elongated tube is formed onto the conforming area to form a torque-transmitting coupling.